题解 | 小红的01子序列构造（easy）

const readline = require('readline');

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
});
let inputCount = 0;
let n = 0, k = 0, s = '';
rl.on('line', function (line) {
    const tokens = line.split(' ');
    // console.log(line, tokens);
    if (inputCount === 0) {
        n = Number(tokens[0]);
        k = Number(tokens[1]);
        inputCount++;
    } else if (inputCount === 1) {
        s = line;
        inputCount++;
    }
    if (inputCount === 2) {
        let left = 0, right = 0;
        let cnt0 = 0, cnt1 = 0;
        let num = 0;
        if (s[0] === '0') {
            cnt0++;
        } else {
            cnt1++;
        }
        while (left < s.length && right < s.length && left <= right) {
            if (num === k) {
                console.log(left + 1, right + 1);
                break;
            } else if (num < k) {
                right++;
                if (right < s.length) {
                    if (s[right] === '0') {
                        cnt0++;
                    } else {
                        num = num + cnt0;
                        cnt1++;
                    }
                }
            } else {
                if (s[left] === '0') {
                    num = num - cnt1;
                    cnt0--;
                } else {
                    cnt1--;
                }
                left++;
            }
        }
        if (left >= s.length || right >= s.length || left > right) console.log(-1);
    }
});

双指针（题目好晦涩难懂）