leetcode-algorithms/src/FindThePivotInteger.java at master · anishLearnsToCode/leetcode-algorithms · GitHub

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// https://leetcode.com/problems/find-the-pivot-integer

// T: O(N)

// S: O(1)

public class FindThePivotInteger {

public int pivotInteger(int n) {

for (int pivot = 1, left = 1, right = summation(n) ; pivot <= n ; pivot++) {

if (left == right) return pivot;

if (left > right) break;

left += pivot + 1;

right -= pivot;

}

return -1;

}

private int summation(int n) {

return (n * (n + 1)) / 2;

}

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