题解 | #DNA序列#

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 arrinput = [];
    while ((line = await readline())) {
        arrinput.push(line);
    }
    let arr = arrinput[0].split("");
    let len = +arrinput[1];
    let resultratio = 0;
    let resultstr = "";
    // 对输入的DNA序列按长度进行遍历，对于每一个片段，求得GC-Ratio，如果比之前求得的更大，那么更新resultratio和resultstr
    for (let i = 0; i <= arr.length - len; i++) {
        let slice = arr.slice(i, i + len);
        let count = 0;
        for (let item of slice) {
            if (item == "C" || item == "G") {
                count++;
            }
        }
        if (count / len > resultratio) {
            resultratio = count / len;
            resultstr = slice.join("");
        }
    }
    console.log(resultstr);
})();