HDU 1711 Number Sequence KMP题解

KMP查找整数数列，不是查找字符串。

原理是一样的，不过把字符串转换为数列，其他基本上是一样的。

#include <stdio.h>#include <string.h>const int MAX_N = 1000001;const int MAX_M = 10001;int strN[MAX_N], strM[MAX_M], next[MAX_M], N, M;void getNext(){memset(next, 0, sizeof(int) * M);for (int i = 1, j = 0; i < M; ){if (strM[i] == strM[j]) next[i++] = ++j;else if (j > 0) j = next[j-1];else i++;}}int kmpSearch(){int i = 0, j = 0;for ( ; M-j <= N-i && j < M; ){if (strN[i] == strM[j]) i++, j++;else if (j > 0) j = next[j-1];else i++;}if (j == M) return i-M+1;//注意题意从1开始return -1;}int main(){int T;scanf("%d", &T);while (T--){scanf("%d %d", &N, &M);for (int i = 0; i < N; i++){scanf("%d", strN+i);}for (int i = 0; i < M; i++){scanf("%d", strM+i);}getNext();printf("%d\n", kmpSearch());}return 0;}