1 国际象棋

本题纯纯归纳总结，对于这种题目，我们应该先针对每一种情况列举出多种用例，这样才能提炼出判断逻辑，而不是抓住一个用例开始随便套规律。这题我卡在判断两步

const readline = require('readline').createInterface({
    input: process.stdin,
    ouput: process.stdout
})

let input = []

readline.on('line', (line) => {
    input.push(line)
})

readline.on('close', () => {
    let t = input[0]
    for (let i = 1; i <= t; i ++) {
        let [x1, y1, x2, y2] = input[i].split(' ').map(Number)
        
        // 一步象
        if (Math.abs(x1 - x2) === Math.abs(y1 - y2)) {
            console.log(1)
            continue
        }
        
        // 一步马
        if (Math.abs(x1 - x2) === 1 && Math.abs(y1 - y2) === 2 ||
            Math.abs(x1 - x2) === 2 && Math.abs(y1 - y2) === 1
        ) {
            console.log(1)
            continue
        }
        
        // 两步象
        if ((Math.abs(x1 - x2) + Math.abs(y1 - y2)) % 2 === 0) {
            console.log(2)
            continue
        }
        
        // 一象一马
        if (Math.abs(x1 - x2 + 3) === Math.abs(y1 - y2) ||
            Math.abs(x1 - x2 - 3) === Math.abs(y1 - y2) ||
            Math.abs(x1 - x2 + 1) === Math.abs(y1 - y2) ||
            Math.abs(x1 - x2 - 1) === Math.abs(y1 - y2)
        ) {
            console.log(2)
            continue
        }
        
        console.log(3)
    }
})

2 挑战boss

简单模拟，感觉难度不如国际象棋（

const readline = require('readline').createInterface({
    input: process.stdin,
    output: process.stdout
})

let input = []

readline.on('line', (line) => {
    input.push(line)
})

readline.on('close', () => {
    let [n, a, b] = input[0].split(' ').map(Number)
    let str = input[1]
    
    let k = 0
    let sum = 0
    
    for (let i = 0; i < n; i ++) {
        sum += (a + k * b)
        if (str[i] === 'o') {
            k ++
        } else {
            k = 0
        }
    }
    
    console.log(sum)
})

3 构造二阶行列式

20 * 20 * 20 * 20，暴力搜索不会超时，第一眼看上去还以为很难qwq

刚开始接受x的代码这样写的：

let x = input[0]

这样得到的x是string类型，导致一直没有输出，记得进行类型转化！

const readline = require('readline').createInterface({
    input: process.stdin,
    output: process.stdout
})

let input = []

readline.on('line', (line) => {
    input.push(line)
})

readline.on('close', () => {
    let x = Number(input[0])
    let flag = 0
    
    outerLoop:
    for (let a = 1; a <= 20; a ++) {
        for (let b = 1; b <= 20; b ++) {
            for (let c = 1; c <= 20; c ++) {
                for (let d = 1; d <= 20; d ++) {
                    if (a * d - b * c === x) {
                        console.log(`${a} ${b}`)
                        console.log(`${c} ${d}`)
                        flag = 1
                        break outerLoop
                    }
                }
            }
        }
    }
    
    if (flag === 0) {
        console.log(-1)
    }
})