advent2024

commit 4fa261e7e673f777b63de4f98918d71a8d6c3490
parent 92ab835688bf0b22bf7707d1890e82db304e8282
Author: bsandro <email@bsandro.tech>
Date:   Sat, 14 Dec 2024 23:02:32 +0200

Day 14 p1

Diffstat:
M
day14/main.cpp
 | 
47
++++++++++++++++++++++++++++++++++++++++++++---

1 file changed, 44 insertions(+), 3 deletions(-)
diff --git a/day14/main.cpp b/day14/main.cpp
@@ -39,17 +39,58 @@ T read_file(const std::string &path) {
     return buf;
 }
 
+void printMap(const Data &robots, const Vec2 &mapSize) {
+    for (int y=0; y<mapSize.y; ++y) {
+        for (int x=0; x<mapSize.x; ++x) {
+            if (std::count_if(robots.begin(), robots.end(), [&x, &y](const Robot &r) {return r.p.x==x&&r.p.y==y;})>0) {
+                std::printf("+");
+            } else std::printf(".");
+        }
+        std::printf("\n");
+    }
+    std::printf("\n");
+}
+
+int countRobots(const Data &robots, const Vec2 &from, const Vec2 &to) {
+    return std::count_if(robots.begin(), robots.end(), [&from, &to](const Robot &r) {
+        return (r.p.x>=from.x && r.p.y<=from.y && r.p.x<=to.x && r.p.y>=to.y);
+    });
+}
+
 int64_t part1(Data input, Vec2 mapSize) {
+    int64_t out = 1;
     std::printf("map size: %dx%d\n", mapSize.x, mapSize.y);
+    //printMap(input, mapSize);
     for (auto &r:input) {
-        std::printf("Robot pos: %d,%d; velocity: %d,%d\n", r.p.x, r.p.y, r.v.x, r.v.y);
+        // std::printf("Robot pos: %d,%d; velocity: %d,%d\n", r.p.x, r.p.y, r.v.x, r.v.y);
+        r.p.x += r.v.x*100;
+        r.p.y += r.v.y*100;
+        r.p.x %= mapSize.x;
+        r.p.y %= mapSize.y;
+        if (r.p.x<0) r.p.x += mapSize.x;
+        if (r.p.y<0) r.p.y += mapSize.y;
+        // std::printf("100s later: %d,%d\n", r.p.x, r.p.y);
     }
-    return 0;
+    printMap(input, mapSize);
+
+    auto quadrantCount = [&input](const Vec2 &from, const Vec2 &to) -> int {
+        int cnt = countRobots(input, from, to);
+        // std::printf("robots in (%d:%d->%d:%d): %d\n", from.x, from.y, to.x, to.y, cnt);
+        return cnt;
+    };
+
+    out *= quadrantCount(Vec2(0, mapSize.y/2-1), Vec2(mapSize.x/2-1, 0));
+    out *= quadrantCount(Vec2(mapSize.x/2+1, mapSize.y/2-1), Vec2(mapSize.x-1, 0));
+    out *= quadrantCount(Vec2(0, mapSize.y-1), Vec2(mapSize.x/2-1, mapSize.y/2+1));
+    out *= quadrantCount(Vec2(mapSize.x/2+1, mapSize.y-1), Vec2(mapSize.x-1, mapSize.y/2+1));
+
+    return out;
 }
 int64_t part2(Data &input [[ maybe_unused ]]) {
     return 0;
 }
-
+// 506 too low
+// 246740364 too high
 int main(int argc, char **argv) {
     Performance perf;
     const std::string fname = argc>1 ? argv[1] : "test1.txt";