题解 | #找出字符串中第一个只出现一次的字符#

#include <cstdio>
#include <cstring>
using namespace std;
int main() {
    int chNumArr[256];
    int firstIdxArr[256];
    char ch, resCh;
    int idx = 0, resIdx = -1;
    memset(chNumArr, 0, sizeof(chNumArr));
    memset(firstIdxArr, -1, sizeof(firstIdxArr));
    while (EOF != scanf("%c", &ch)) {
        if(ch == '\n') {
            for(int i=0; i<256; i++){
                if(chNumArr[i] != 1) {
                    continue;
                }
                if(resIdx == -1) {
                    resCh = i;
                    resIdx = firstIdxArr[i];
                } else if(firstIdxArr[i] < resIdx) {
                    resCh = i;
                    resIdx = firstIdxArr[i];
                }
            }
            if(resIdx == -1) {
                printf("-1\n");
            } else {
                printf("%c\n", resCh);
            }
            idx = 0;
            resIdx = -1;
            memset(chNumArr, 0, sizeof(chNumArr));
            memset(firstIdxArr, -1, sizeof(firstIdxArr));
        } else {
            chNumArr[ch]++;
            if(firstIdxArr[ch] == -1) {
                firstIdxArr[ch] = idx;
            }
            idx++;
        }
    }
    return 0;
}