416. Partition Equal Subset Sum (#66)

Author: Kohei Asai

solutions/partitionEqualSubsetSum.test.ts

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+import canPartition from "./partitionEqualSubsetSum";
+
+describe("416. Partition Equal Subset Sum", () => {
+  test("#1", () => {
+    expect(canPartition([1, 5, 11, 5])).toBe(true);
+  });
+
+  test("#2", () => {
+    expect(canPartition([1, 2, 3, 5])).toBe(false);
+  });
+
+  test("#3", () => {
+    expect(canPartition([8, 6, 3, 4, 5])).toBe(true);
+  });
+});

solutions/partitionEqualSubsetSum.ts

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+// 416. Partition Equal Subset Sum
+// https://leetcode.com/problems/partition-equal-subset-sum/
+function canPartition(nums: number[]): boolean {
+  const total = nums.reduce((total, num) => total + num, 0);
+
+  if (total % 2 !== 0) return false;
+
+  const target = total / 2;
+  const dp = new Array(total + 1).fill(false);
+
+  dp[0] = true;
+
+  for (const num of nums) {
+    if (dp[target - num]) return true;
+
+    for (let i = target; i >= num; --i) {
+      dp[i] = dp[i - num];
+    }
+  }
+
+  return false;
+}
+
+export default canPartition;