ZOJ 3171 The Hidden 7's

#include <iostream>#include <memory.h>#include <cstdio>using namespace std;const int maxn = 10001;char str[maxn];long long dp[6];int main(){while (~scanf("%s", str)){memset(dp, 0, sizeof(dp));int len = strlen(str);for (int i = 0; i < len; ++i){str[i] = tolower(str[i]);if(str[i] == 's'){dp[0]++;}else if(str[i] == 'e'){dp[1] += dp[0];dp[3] += dp[2];}else if(str[i] == 'v'){dp[2] += dp[1];}else if(str[i] == 'n'){dp[4] += dp[3];}}printf("%lld\n", dp[4]);}return 0;}