bruteforced 17b; 17a was calced in mind

Author: grrz

.idea/codeStyles/codeStyleConfig.xml

@@ -0,0 +1,68 @@
+type range = [number, number];
+// type Coords = {x: number, y: number};
+type Area = {x: range, y: range}
+enum HitResult { miss, hit, over }
+
+const input17: Area = {x: [144, 178], y: [-100, -76]};
+const input17_sample: Area = {x: [20, 30], y: [-10, -5]};
+
+function checkHit(area: Area, x: number, y: number): HitResult {
+  if (x >= area.x[0] && x <= area.x[1] && y >= area.y[0] && y <= area.y[1]) return HitResult.hit;
+  if (x > area.x[1] || y < area.y[0]) return HitResult.over;
+  return HitResult.miss;
+}
+
+function maxStepsV(r: number): number {
+  let s = 1;
+  while (s < r) { r -= s; s++; }
+  return s;
+}
+
+function calcThrow(area: Area, vx: number, vy: number): HitResult {
+  let x = 0;
+  let y = 0;
+  let res = HitResult.miss;
+
+  while (res === HitResult.miss) {
+    x += vx;
+    y += vy--;
+    if (vx > 0) vx--;
+    res = checkHit(area, x, y);
+  }
+
+  return res;
+}
+
+// const sampleCheckValuesRaw = [23,-10,  25,-9,   27,-5,   29,-6,   22,-6,   21,-7,   9,0,     27,-7,   24,-5, 25,-7  , 26,-6 ,  25,-5 ,  6,8   ,  11,-2 ,  20,-5 ,  29,-10,  6,3   ,  28,-7, 8,0    , 30,-6 ,  29,-8 ,  20,-10,  6,7   ,  6,4   ,  6,1   ,  14,-4 ,  21,-6, 26,-10 , 7,-1  ,  7,7   ,  8,-1  ,  21,-9 ,  6,2   ,  20,-7 ,  30,-10,  14,-3, 20,-8  , 13,-2 ,  7,3   ,  28,-8 ,  29,-9 ,  15,-3 ,  22,-5 ,  26,-8 ,  25,-8, 25,-6  , 15,-4 ,  9,-2  ,  15,-2  , 12,-2 ,  28,-9 ,  12,-3 ,  24,-6 ,  23,-7, 25,-10 , 7,8   ,  11,-3 ,  26,-7  , 7,1   ,  23,-9 ,  6,0   ,  22,-10,  27,-6, 8,1    , 22,-8 ,  13,-4 ,  7,6    , 28,-6 ,  11,-4 ,  12,-4 ,  26,-9 ,  7,4, 24,-10 , 23,-8 ,  30,-8 ,  7,0    , 9,-1  ,  10,-1 ,  26,-5 ,  22,-9 ,  6,5, 7,5   ,  23,-6 ,  28,-10,  10,-2  , 11,-1 ,  20,-9 ,  14,-2 ,  29,-7 ,  13,-3, 23,-5 ,  24,-8 ,  27,-9 ,  30,-7  , 28,-5 ,  21,-10,  7,9   ,  6,6   ,  21,-5, 27,-10,  7,2   ,  30,-9 ,  21,-8  , 22,-7 ,  24,-9 ,  20,-6 ,  6,9   ,  29,-5, 8,-2  ,  27,-8 ,  30,-5 ,  24,-7];
+// const sampleCheckValues: { [id: string]: number } = {};
+// while (sampleCheckValuesRaw.length > 0) sampleCheckValues[`${<number> sampleCheckValuesRaw.shift()}, ${<number> sampleCheckValuesRaw.shift()}`] = 1;
+
+function B(area: Area): number {
+  // calc min-max initial velocity ranges
+  const mmvx: range = [
+    maxStepsV(area.x[0]), // max number of steps to reach
+    area.x[1] // one max step forward
+  ];
+
+  const mmvy: range = [
+    area.y[0], // one max step down
+    -area.y[0] // highest throw
+  ];
+
+  console.log(mmvx, mmvy);
+
+  let n = 0;
+  for (let vx = mmvx[0]; vx <= mmvx[1]; vx++)
+    for (let vy = mmvy[0]; vy <= mmvy[1]; vy++)
+      if (calcThrow(area, vx, vy) === HitResult.hit) {
+        // console.log(vx, vy);
+        // delete sampleCheckValues[`${vx}, ${vy}`];
+        n++;
+      }
+
+  // console.log(Object.keys(sampleCheckValues));
+  return n;
+}
+
+// console.log(B(input17_sample));
+console.log(B(input17));