day 12

d12.cc

@@ -0,0 +1,161 @@
+#include <iostream>
+#include <vector>
+#include <complex>
+#include <deque>
+
+//#define ANIMATE
+
+using namespace std;
+
+struct Input {
+    vector<vector<unsigned char>> map;
+    unsigned width;
+    unsigned height;
+    complex<int> start;
+    complex<int> end;
+};
+
+complex<int> dirs[] = {
+    complex<int>(1, 0),
+    complex<int>(0, 1),
+    complex<int>(-1, 0),
+    complex<int>(0, -1)
+};
+
+Input parse()
+{
+    Input data;
+    auto &map = data.map;
+    for (string line; getline(cin, line);) {
+        vector<unsigned char> row;
+        for (auto x : line) {
+            switch (x) {
+            case 'S':
+                data.start = complex<int>(row.size(), map.size());
+                row.push_back('a' - 'a');
+                break;
+            case 'E':
+                data.end = complex<int>(row.size(), map.size());
+                row.push_back('z' - 'a');
+                break;
+            default: row.push_back(x - 'a'); break;
+            }
+        }
+        data.map.push_back(row);
+    }
+    data.width = map.front().size();
+    data.height = map.size();
+    return data;
+}
+
+#ifdef ANIMATE
+#include <fstream>
+unsigned render_frame = 0;
+void render(const Input &input, vector<vector<unsigned>> &dist, deque<complex<int>> &scan)
+{
+    auto scan_map = (bool (*)[input.width])new bool[input.width * input.height]();
+    for (auto &x : scan) {
+        scan_map[x.imag()][x.real()] = true;
+    }
+
+    char fname[] = "img/00000.pam";
+    sprintf(fname, "img/%05u.pam", render_frame++);
+    auto file = ofstream(fname);
+    file << "P7\n";
+    file << "WIDTH " << input.width << '\n';
+    file << "HEIGHT " << input.height << '\n';
+    file << "DEPTH 3\nMAXVAL 255\nTUPLTYPE RGB\nENDHDR\n";
+
+    unsigned maxdist = 0;
+    for (unsigned y = 0; y < input.height; y++) {
+        for (unsigned x = 0; x < input.width; x++) {
+            unsigned d = dist[y][x];
+            if (d > maxdist) maxdist = d;
+        }
+    }
+
+    for (unsigned y = 0; y < input.height; y++) {
+        for (unsigned x = 0; x < input.width; x++) {
+            uint32_t color = 0;
+            color |= ((dist[y][x] * 0xFF / maxdist) & 0xFF) << 8;
+            color |= input.map[y][x] * 0xFF / 26;
+            if (scan_map[y][x]) color = 0xFF0000;
+            file.write((char *)&color, 3);
+        }
+    }
+    file.close();
+    delete scan_map;
+}
+#endif
+
+vector<vector<unsigned>> calc_dist(const Input &input)
+{
+    vector<vector<unsigned>> dist(input.height, vector<unsigned>(input.width));
+    auto &map = input.map;
+
+    deque<complex<int>> scan;
+    scan.push_back(input.end);
+    dist[input.end.imag()][input.end.real()] = 1;
+
+    while (!scan.empty()) {
+        auto pos = scan.front();
+        unsigned pos_d = dist[pos.imag()][pos.real()];
+        unsigned pos_h = map[pos.imag()][pos.real()];
+        scan.pop_front();
+
+        for (auto dir : dirs) {
+            auto newpos = pos + dir;
+
+            // Make sure the new position is in-bounds
+            if (newpos.imag() < 0 || newpos.imag() >= (int)input.height) continue;
+            if (newpos.real() < 0 || newpos.real() >= (int)input.width) continue;
+
+            // If the distance for this position has already been calculated,
+            //  and is smaller than the current pos' distance, skip it.
+            unsigned &newpos_d = dist[newpos.imag()][newpos.real()];
+            if (newpos_d && newpos_d <= pos_d + 1) continue;
+
+            // Make sure the height difference isn't too big
+            unsigned newpos_h = map[newpos.imag()][newpos.real()];
+            if ((int)pos_h - (int)newpos_h > 1) continue;
+
+            // Otherwise, continue down this path
+            newpos_d = pos_d + 1;
+            scan.push_back(newpos);
+        }
+#ifdef ANIMATE
+        render(input, dist, scan);
+#endif
+    }
+    return dist;
+}
+
+unsigned p1(const Input &input, const vector<vector<unsigned>> &dist)
+{
+    unsigned end_dist = dist[input.start.imag()][input.start.real()];
+    if (end_dist) end_dist--;
+    return end_dist;
+}
+
+unsigned p2(const Input &input, const vector<vector<unsigned>> &dist)
+{
+    unsigned smallest = dist[input.start.imag()][input.start.real()];
+    for (unsigned y = 0; y < input.height; y++) {
+        for (unsigned x = 0; x < input.width; x++) {
+            if (input.map[y][x] == 0) {
+                unsigned d = dist[y][x];
+                if (d && d < smallest) smallest = d;
+            }
+        }
+    }
+    if (smallest) smallest--;
+    return smallest;
+}
+
+int main()
+{
+    auto input = parse();
+    auto dist = calc_dist(input);
+    cout << p1(input, dist) << endl;
+    cout << p2(input, dist) << endl;
+}

d12_input.txt

@@ -0,0 +1,41 @@
+abcccccccccccccccccaaccccccccccccaaaaaaaacccccccccccaaaaaccccaaaaaaccaaaaaaaaaaaaaaaaaccccccccccccccccaaacccccaaaaaaaacccaaaccccccccccccccccccccccccccccccccccccccccccccccccccaaaaa
+abccccccccccccccccaaacaacccccccccccaaaacccccccccccccaaaaaacccaaaaaaccaaaaaaaaaaaaaaaaaaaacccccccccaaacaaacccccaaaaaaaaaccaaaaccccccccccccccccccccccccccccccccccccccccccccccccaaaaaa
+abcccccccccccccccccaaaaacccccccccccaaaaaccccccccccccaaaaaaccccaaaacccaaaacccaaaaaaaaaaaaacccccccccaaaaaaaaaacccaaaaaaaaccaaaaccccccccccccccccccccccccccccccccccaaacccccccccccaaaaaa
+abcccccccccccccccaaaaaacccccccccccaaacaaccaaccccccccaaaaaaccccaaaacccaaaccccaaaaaaaaaaaaaccccccccccaaaaaaaaaccaaaaaacccccaaacccccccccccccccccccccccccccccccccccaaaccccccccccccccaaa
+abcccccccccccccccaaaaaaaacccccccccaacccacaaacaacccccccaaccccccaccaccccccccaaaaaaaaaaaaccccccccccccccaaaaaaacccaaaaaaacccccccccccccaacccccccccccccccccccccccccccaaaccccccccccccccaaa
+abcccccccccccccccaacaaaaacccccccccccccccccaaaaacccccccccccccccccccccccccccaaaaaaaaaaaaccccccccccccccaaaaaaccccaaccaaacccccccccccaaaaaaccccccccccccccccccccccccccdccccccccccccccccaa
+abccaacccccccaaacccaaacaccccccccccaaacccaaaaaaccccccccccccccccccccccccccccaaacccaaaaaacaaaaccccccccaaaaaaaccccccccaaacccccccccccaaaaaacccccccccccccccccllllllcccdddddcccccccccccccc
+abaaaacccacccaaccccaacccccccccccccaaacccaaaaaaaacccccccccccccccccaaccccccccacccaaaaccccaaaaccccccccaaacaaaccccccccccccccccccccccaaaaaaccccccccccccccccllllllllldddddddddddccaaccccc
+abaaaaccaaaaaaaacccccccccccccccaaaaaaaacaacaaaaacccccccccccccccccaaacccccccaaacaaccccccaaaacccccccccccccaaccccccccccccccccccccccaaaaaccccccccccccccccclllllllllldddddddddeeaaaccccc
+abaaaccccaaaaaaaaccccccccaaacccaaaaaaaacccaaacccccccccccccccccaaaaaaaaccccccaaaaacccccccaacccccccccccccccccccccccccccccccccccccccaaaaccccaaaccccccccckllppppplllmmmmmmmdeeeeaaccccc
+abaaaacccaaaaaaaaacccccaaaaaaccccaaaaaccccaaccccccccccccccccccaaaaaaaaccccccaaaaaaacccccccccccccccccccccccccccccccccccccccccccccccccccccaaaacccccccckklpppppppplmmmmmmmmmeeeeaccccc
+abaaaacccaaaaaaaaacccccaaaaaacccaaaaaaccccccccaacccccccccccccccaaaaaaccccccaaaaaaaacccccccccccccccccccccccccccccccccccccccccccccccccccccaaaacccccccckkkppppppppqmmmmmmmmmmeeeaacccc
+abaaaaaccaaaaaaaaccccccaaaaaacccaaaaaaccccccacaaaacccccccccccccaaaaaaccccccaaaaaaaaccccccccaaaaccccccccaaacccccccccccccccccccccccccccccccaaacccccccckkkpppuuuppqqqqqqqqmmmeeeeacccc
+abacccccaaaaaaaccccccccaaaaaccccaccaaaccccccaaaaaacccccacccccccaaaaaaccccccaaaaaacaaaccccccaaaaccccccccaaaacccccccccccccccccccccccccccccccccccccccckkkpppuuuuuuqqqqqqqqqnnneeeccccc
+abcccccccaccaaaccccccccaaaaacccccccccccccccccaaaacccaaaacccccccaacaaacccccccccaaacaaaaaccccaaaaccccccccaaaaccccccccccccccccccccccccccccccccccccccckkkkpppuuuuuuuqvvvvqqqnnneeeccccc
+abcccccccccccaaacaaccccccccccccccccccccccccccaaaacccaaaaaacccccccccccccccccccccccaaaaaaccccaaacccccccccaaaccccccccccccccccccccccccccccccccccccccckkkkrrpuuuxxxuvvvvvvvqqnnneeeccccc
+abcccccccccccccccaacaaaccccccccccccccccccccccaacaacccaaaaacccccccccccccccccccccccaaaaaaccccccccccccccccccccccccccccccccccccccccccccccccccccccccckkkkrrrruuxxxxuvvvvvvvqqnnneeeccccc
+abcccccccccccccccaaaaacccccccccccccccccccccccccccaccaaaaacccccaaccccccccccccccccccaaaaaccccccccccccccccaaaccccccccccccccaaacccccccccccccccccccckkkkrrrruuuxxxxyyyyyvvvqqnnneecccccc
+abcccccccccccccaaaaaacccccccccccaacaacccccccccccaaaaaaaaacccacaaaacaaccaaccccccccaaacaaccccccccccaaccccaaaaaacccaacaacccaaacacccccccccccccccccjjkkrrrruuuuuxxxyyyyyvvqrqnneffcccccc
+abcccccccccccccaaaaaaaacccaaacccaaaaaccccccaacccaaaaaaaaacccaaaaaacaaaaaaccccccccaaacaaacccccccaaaaaacaaaaaaacccaaaaacaaaaaaaaccccccccccccccccjjjrrrtttuuxxxxxyyyyyvvrrnnnfffcccccc
+SbccccccccccccccccaaaaacccaaaaccaaaaaaccccaaaaaacaaaaaaaaacccaaaacccaaaaaccccccccaaaaaaacccccccaaaaaaaaaaaaaaccaaaaaccaaaaaaaaccccccccccccccccjjjrrrtttxxxEzzzzyyyvvrrrnnnfffcccccc
+abccccccccccaaaccaaccaacccaaaaccaaaaaacccccaaaaacaaaaaaaaacccaaaaccaaaaaacccccccccaaaaaaccccccccaaaacaaaaaaacccaaaaaaccaaaaaacccccccccccccccccjjjrrrtttxxxxxyyyyyyvvrrrnnnfffcccccc
+abcccccccccaaaaccaacccccccaaacccaaaaaacccaaaaaaaaaaaaaaaaacccaacacaaaaaaaacccccaaaaaaaacccccccccaaaacccaaaaaaccccaaaacccaaaaacccccccccccccccccjjjrrrtttxxxxxyyyyyyywvrrnnnfffcccccc
+abcccccccccaaaacccccccccccccccccccaaaccccaaaaaaaaaaaaaaaaaacccccccaaaaaaaacccccaaaaaaaaaccccccccaccacccaaaaaaccccacccccaaaaaacccccccccccccccccjjjrrrrttttxxxyyyyyyywwrrroooffcccccc
+abccccccccccaaaccccccccccccccccccccccccccaaaaaaaaaccaaaaaaaccccccccccaaccccccccaaaaaaaaaaccccccccccccccaacccccccccccccccaaccccccccccccccccccccjjjjqqqqttttxxyywwwwwwwwrrooofffccccc
+abcccccccccccccccccccccccccccccccccccccccccaaacacccccaaaaccccccccccccaacccccccccccaaacaaacccccccccccccccccccccccccccccaaacccccccccccccccccccaacjjjjqqqqqttwwwwwwwwwwwrrrooofffccccc
+abcccccccccccccccccccccccccccccccccccccccccaaccccccccccaacccccccccccccccccccccccccaaacccccccccccccccccccccccccccccccccaaacccccccccccccccccaaaaaajjjjqqqqttwwwwwwsswwrrrrooofffccccc
+abcccccaaaaccccccccccccccaacaaccccccccccccccccccccccccccccccccccccccccccccccccccccaacccccccccccccccccccccccccccccccaaaaaaaaccaaaacccccccccaaaaaacjjjiqqqtttwwwwsssssrrrrooofffccccc
+abccccaaaaaccccccccccccccaaaaacccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccaaaaaaaaccaaaaacccccccccaaaaacciiiiqqttswwwssssssrrroooogffccccc
+abccccaaaaaacccccccccccccaaaaaacccaaaccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccaaaaaccaaaaaaccccccccaaaaacccciiiqqqssssssspppooooooogggaccccc
+abccccaaaaaaccccccccaacccaaaaaaccccaacccccccccccccccccccccccccccccccccaaaaccccccccccccccccccccccccccccccccccccccccccaaaaaaccaaaaaaccccccccaaaaaccccciiiqqsssssspppppoooooggggaacccc
+abccccaaaaaccccccaaaaacccaaaaaacaacaaaaaccccccccccccccccccccaacccccccaaaaacccccccccccaaaccccccccccccccccccccccccccccaaaaaacccaaaaacccccccccacccccccciiiqqqpssspppppgggggggggaaacccc
+abccccccaaacccccccaaaaaccccaaaccaaaaaaaacccccccaacccccccaaccaacccccccaaaaaacccccccccaaaacccccccccccaaaaccccccccccccaaccaaacccaaacccccaaacaaaccccccccciiqqppppppphhhggggggggaaaacccc
+abccccccccccccccccaaaaaccccccccccaaaaaccccccccaaacaaccccaaaaaacccccccaaaaaaaccccccccaaaacccccccccccaaaacccccccccaaaaaacccccccccccccccaaaaaaaccccccccciiippppppphhhhggggggcaaacccccc
+abaacccccccccccccaaaaaccccccccccccaaaaaccccccccaaaaacccccaaaaaaacccccaaaaacaaacccccccaaacccccccccccaaaacccccccccaaaaacccccccccccccccccaaaaaacccccccccciiiippphhhhhhcccccccaaacccccc
+abaacccccccccccccccaaacccccccccccaaacaaccccccaaaaaaccccccaaaaaaacccaaccaaacaaaaccaaaccccccccccccccccaaacccccccccaaaaaaacccccccccccccccaaaaaaaacccccccciiihhhhhhhhaaaccccccccccccccc
+abaaccccccccccccccccccccccccccccccaacccccccccaaaaaaaacccaaaaaaccaaaaaacccccaaaacaaaaaccccccccccccccccccccccccccaaaaaaaaccccccccccccccaaaaaaaaaccccccccciihhhhhhcaaaacccccccccccccca
+abaaccccccccccccccccccccccccccccccccaacccccccaacaaaaacccaaaaaaccaaaaacccccccaaaaaaaacccccccccccccccccccccccccccaaaaaaaacccccccccaaacaaaaaaaaaacccccccccccchhhaccccaacccccccccccccca
+abaaccccccccccccccccccccccccccccccccaaaaaaccccccaaccccccccccaaccaaaaaaacccccaaaaaaaccccccccccccccccccccccccaaaccacaaacccccccccccaaaaaaacaaacaaaaaacccccccccaaacccccccccccccccaaaaaa
+abccccccccccccccccccccccccccccccccccaaaaaccccccaaccccccccccccccaaaaaaaacaaaaaaaaaaccccccccccccccccccccccccaaaaaaccaaaccccccccccccaaaaaacaaacaaaaaacccccccccaaaccccccccccccccccaaaaa
+abccccccccccccccccccccccccccccccccaaaaaaaacccccccccccccccccccccaaaaaaaacaaaaaaaaaaaaacccccccccccccccccccccaaaaaacccccccccccccccaaaaaaaaaaaaaaaaaacccccccccccccccccccccccccccccaaaaa

d12_output.txt

@@ -0,0 +1,2 @@
+484
+478

makeanim.sh

@@ -1,13 +1,4 @@
 #!/bin/sh
-rm img/*.gif
+ffmpeg -threads 0 -pattern_type glob -i "img/*.pam" -r 60 \
-waitjobs() {
+    -filter:v "setpts=0.05*PTS,scale=iw*4:ih*4:flags=neighbor" \
-    while [ "$(jobs -p | wc -l)" -ge "$1" ]; do wait; done
+    anim.webm
-}
-for x in img/*.pam; do
-    echo "$x"
-    pamtogif -quiet "$x" > "$x.gif" &
-    waitjobs "$(nproc)"
-done
-wait
-gifsicle -d1 --verbose img/*.gif > anim.gif
-ffmpeg -i anim.gif -filter:v "setpts=0.1*PTS,scale=iw*4:ih*4:flags=neighbor" -r 100 anim.webm