Create index.ts

Author: masx200

sum-of-subsequence-widths/index.ts

@@ -0,0 +1,13 @@
+export default function sumSubseqWidths(nums: number[]): number {
+
+    const MOD = 1000000007;
+    nums.sort((a, b) => a - b);
+    let res = 0;
+    let x = nums[0], y = 2;
+    for (let j = 1; j < nums.length; j++) {
+        res = (res + nums[j] * (y - 1) - x) % MOD;
+        x = (x * 2 + nums[j]) % MOD;
+        y = y * 2 % MOD;
+    }
+    return (res + MOD) % MOD;
+}