华为可信科目一完整试学：复杂度、边界测试与错误定位

C++17 · 可运行示例

#include <iostream>
#include <vector>
using namespace std;

int main() {
    int n;
    if (!(cin >> n)) return 0;
    vector<int> values(n);
    for (int& value : values) cin >> value;
    int target;
    cin >> target;

    int left = 0;
    int right = n;
    while (left < right) {
        int mid = left + (right - left) / 2;
        if (values[mid] >= target) right = mid;
        else left = mid + 1;
    }
    if (left == n) cout << -1 << '\n';
    else cout << left << ' ' << values[left] << '\n';
    return 0;
}

编译与运行命令

clang++ -std=c++17 -O2 -Wall -Wextra main.cpp -o main && ./main

C11 · 可运行示例

#include <stdio.h>
#include <stdlib.h>

int main(void) {
    int n;
    if (scanf("%d", &n) != 1) return 0;
    int *values = malloc((size_t)n * sizeof(*values));
    if (n > 0 && values == NULL) return 1;
    for (int i = 0; i < n; ++i) scanf("%d", &values[i]);
    int target;
    scanf("%d", &target);
    int left = 0, right = n;
    while (left < right) {
        int mid = left + (right - left) / 2;
        if (values[mid] >= target) right = mid;
        else left = mid + 1;
    }
    if (left == n) puts("-1");
    else printf("%d %d\n", left, values[left]);
    free(values);
    return 0;
}

编译与运行命令

gcc -std=c11 -O2 main.c -o main && ./main

Java 17 · 可运行示例

import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner scanner = new Scanner(new BufferedInputStream(System.in));
        if (!scanner.hasNextInt()) return;
        int n = scanner.nextInt();
        int[] values = new int[n];
        for (int i = 0; i < n; i++) values[i] = scanner.nextInt();
        int target = scanner.nextInt();

        int left = 0;
        int right = n;
        while (left < right) {
            int mid = left + (right - left) / 2;
            if (values[mid] >= target) right = mid;
            else left = mid + 1;
        }
        if (left == n) System.out.println(-1);
        else System.out.println(left + " " + values[left]);
    }
}

编译与运行命令

javac Main.java && java Main

Python 3.11 · 可运行示例

import sys

def main() -> None:
    tokens = list(map(int, sys.stdin.buffer.read().split()))
    if not tokens:
        return
    n = tokens[0]
    values = tokens[1:1 + n]
    target = tokens[1 + n]

    left = 0
    right = n
    while left < right:
        mid = left + (right - left) // 2
        if values[mid] >= target:
            right = mid
        else:
            left = mid + 1
    if left == n:
        print(-1)
    else:
        print(left, values[left])

if __name__ == "__main__":
    main()

编译与运行命令

python3 main.py