const rl = require("readline").createInterface({ input: process.stdin }); function dcsl_sum(a1, d, n) { return n * a1 + (n * (n - 1) * d) / 2; } rl.on("line", (input) => { //分治思想:n为偶数 // if ((input * 1) % 2 === 0) { // n = input / 2; // z_sum = dcsl_sum(1, 2, n); // f_sum = dc...