题解 | 小红的双生串

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void (async function () {
    // Write your code here
    while ((line = await readline())) {
        let tokens = line.split(" ");
        let a = tokens[0];
        let forntStr = a.substring(0, a.length / 2);
        let endStr = a.substring(a.length / 2);
        if (forntStr === endStr) {
            console.log(0);
        }
        const firstWord = forntStr.substring(0, 1);
        const endWord = endStr.substring(endStr.length - 1);
        let count = 0;
        let mapFornt = {},
            mapEnd = {};
        for (let i = 0; i < forntStr.length; i++) {
            //前半部分
            let keys = Object.keys(mapFornt);
            let forntVal = forntStr.substring(i, i + 1);
            if (keys.indexOf(forntVal) === -1) {
                mapFornt[forntVal] = 1;
            } else {
                mapFornt[forntVal] += 1;
            }
            //后半部分
            let _keys = Object.keys(mapEnd);
            let endVal = endStr.substring(i, i + 1);
            if (_keys.indexOf(endVal) === -1) {
                mapEnd[endVal] = 1;
            } else {
                mapEnd[endVal] += 1;
            }
        }

        let max = 0,
            k = 0,
            _keys = Object.keys(mapFornt);
        while (k < _keys.length) {
            max = Math.max(max, mapFornt[_keys[k]]);
            k++;
        }

        count = forntStr.length - max;
        max = 0;
        k = 0;
        _keys = Object.keys(mapEnd);

        while (k < _keys.length) {
            max = Math.max(max, mapEnd[_keys[k]]);
            k++;
        }

        count += forntStr.length - max;
        console.log(count);
    }
})();