[leet] candy (greedy) (mid)

Author: hyeonbinHur

허현빈/7주차/260212-1.js

@@ -0,0 +1,28 @@
+/**
+ * @param {number[]} h
+ * @return {number}
+ */
+var trap = function (h) {
+  const n = h.length;
+  if (n === 0) return 0;
+
+  const leftMax = new Array(n).fill(0);
+  const rightMax = new Array(n).fill(0);
+
+  leftMax[0] = h[0];
+  for (let i = 1; i < n; i++) {
+    leftMax[i] = Math.max(leftMax[i - 1], h[i]);
+  }
+
+  rightMax[n - 1] = h[n - 1];
+  for (let i = n - 2; i >= 0; i--) {
+    rightMax[i] = Math.max(rightMax[i + 1], h[i]);
+  }
+
+  let totalWater = 0;
+  for (let i = 0; i < n; i++) {
+    totalWater += Math.min(leftMax[i], rightMax[i]) - h[i];
+  }
+
+  return totalWater;
+};

허현빈/7주차/260212-2.js

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+/**
+ * @param {number[]} ratings
+ * @return {number}
+ */
+var candy = function (ratings) {
+  const n = ratings.length;
+  const ans = new Array(n).fill(1);
+
+  for (let i = 1; i < n; i++) {
+    if (ratings[i] > ratings[i - 1]) {
+      ans[i] = ans[i - 1] + 1;
+    }
+  }
+
+  for (let i = n - 2; i >= 0; i--) {
+    if (ratings[i] > ratings[i + 1]) {
+      ans[i] = Math.max(ans[i], ans[i + 1] + 1);
+    }
+  }
+
+  return ans.reduce((a, b) => a + b, 0);
+};