Given N integers, you are supposed to find the smallest positive integer that is NOT in the given list.
Each input file contains one test case. For each case, the first line gives a positive integer N (≤10?5??). Then N integers are given in the next line, separated by spaces. All the numbers are in the range of int.
Print in a line the smallest positive integer that is missing from the input list.
10
5 -25 9 6 1 3 4 2 5 17
7
#include <stdio.h> #include <algorithm> #include <limits.h> #include <set> using namespace std; int main() { int n; scanf("%d", &n); set<int> st; for (int i = 0; i < n; i++) { int tmp; scanf("%d", &tmp); if (tmp > 0) { st.insert(tmp); } } int j = 1; for (auto it = st.begin(); it != st.end(); it++) { if (*it > j) { printf("%d", j); break; } else j++; } if(j==st.size()+1)printf("%d",j); }
注意点：这里只保证了输入数不超过int大小，用hash不好做，不如直接用set，自动升序排列，找到第一个不满足的数。
第二个坑是测试点2-5都是输入数据连续的，缺失的是输入数据后面那个数
PAT A1144 The Missing Number （20 分）
原文：https://www.cnblogs.com/tccbj/p/10409113.html