[C++知识库]C++程序题-2021.08.20

题目描述

给你一个主键清单，该清单无序且每个元素均为整型，每个整数范围为[-999999,999999]，请输出首个不在主键清单中的正整数。
e.g:
输入：[8,-1,3,9,5] 输出：1
输入：[0,1,2,3,4,5,6,7] 输出：8

参考代码

#include<stdio.h>
#include<stdlib.h>
#include <vector>
#include <iostream>
using namespace std;

typedef struct
{
    int* elem;
    int length;
    int listsize;
}sqlist;

bool initlist_sq(sqlist& L, int LISTINITSIZE)
{
    L.elem = (int*)malloc(LISTINITSIZE * sizeof(int));
    if (!L.elem)
        return false;
    L.length = 0;
    L.listsize = LISTINITSIZE;
    return true;
}

int cft(int* arr, int arrLen) {
    int* ptr = arr;
    int tmp;
    sqlist La, Lb;
    initlist_sq(La, arrLen);
    initlist_sq(Lb, arrLen);
    La.length = arrLen;
    Lb.length = La.length + 1;
    int i;
    for (i = 0; i < La.length; i++) {
        tmp = *ptr;
        La.elem[i] = tmp;
        ptr++;
    }
       

    for (i = 1; i <= Lb.length; i++)
        Lb.elem[i] = 0;
    for (i = 0; i < La.length; i++)
        if (La.elem[i] >= 1)
            Lb.elem[La.elem[i]] = 1;
    for (i = 1; i <= Lb.length; i++)
        if (Lb.elem[i] == 0)
            break;
    return i;
}

int main()
{
    int input[5] = {8,-1,3,9,5 };

    int ret = cft(input,5);
    cout << ret << endl;
    
    return 0;
}