Create 923-3sum-with-multiplicity.js

Author: everthis

923-3sum-with-multiplicity.js

@@ -0,0 +1,18 @@
+/**
+ * @param {number[]} A
+ * @param {number} target
+ * @return {number}
+ */
+const threeSumMulti = function(A, target) {
+  const d = {};
+  let res = 0;
+  const mod = Math.pow(10, 9) + 7;
+  for (let i = 0; i < A.length; i++) {
+    res += d[target - A[i]] >= 0 ? d[target - A[i]] : 0;
+    res %= mod;
+    for (let j = 0; j < i; j++) {
+      d[A[i] + A[j]] = (d[A[i] + A[j]] || 0) + 1;
+    }
+  }
+  return res % mod;
+};