You are given a binary string s. You are allowed to perform two types of operations on the string in any sequence: Type-1: Remove the character at the start of the string s and append it to the end of the string. Type-2: Pick any character in s and

minFlips.js

/**
 * @param {string} s
 * @return {number}
 */
var minFlips = function(s) {
    const n = s.length;
    const s2 = s + s;

    // Build alternating patterns of length 2n
    let alt0 = "", alt1 = "";
    for (let i = 0; i < 2 * n; i++) {
        alt0 += i % 2 === 0 ? "0" : "1";
        alt1 += i % 2 === 0 ? "1" : "0";
    }

    let diff0 = 0, diff1 = 0;
    let res = Infinity;

    let left = 0;
    for (let right = 0; right < 2 * n; right++) {
        if (s2[right] !== alt0[right]) diff0++;
        if (s2[right] !== alt1[right]) diff1++;

        // Once window size exceeds n, shrink from left
        if (right - left + 1 > n) {
            if (s2[left] !== alt0[left]) diff0--;
            if (s2[left] !== alt1[left]) diff1--;
            left++;
        }

        // When window size is exactly n, update result
        if (right - left + 1 === n) {
            res = Math.min(res, diff0, diff1);
        }
    }

    return res;
};