题解 | 被打乱的异或和

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
    let params = [];
    while ((line = await readline())) {
        let tokens = line.split(" ");
        // let a = parseInt(tokens[0]);
        // let b = parseInt(tokens[1]);
        // console.log(a + b);
        params.push(tokens);
    }
    // console.log(params);
    let n = parseInt(params[0][0]); // 多少个测试案例
    // 对每个test case 进行遍历
    for (let i = 1; i < params.length; i += 2) {
        let length = parseInt(params[i][0]); // 新数组长度
        let arr = params[i + 1].map((v) => parseInt(v)); // 新数组的内容
        // console.log(length,arr)
        for (let j = 0; j < length; j++) {
            // 把非j项过滤然后取异或结果
            if (arr.filter((value, index) => index != j).reduce((acc,num)=>acc^num,0) == arr[j]) {
                // tmp_result = 0;
                console.log(arr[j]);
                break;
            }
        }
    }
})();