codeforces 535D. Tavas and Malekas KMP

题目链接

又复习了一遍kmp....之前都忘光了

 #include<bits/stdc++.h>
 using namespace std;
 #define pb(x) push_back(x)
 #define ll long long
 #define mk(x, y) make_pair(x, y)
 #define lson l, m, rt<<1
 #define mem(a) memset(a, 0, sizeof(a))
 #define rson m+1, r, rt<<1|1
 #define mem1(a) memset(a, -1, sizeof(a))
 #define mem2(a) memset(a, 0x3f, sizeof(a))
 #define rep(i, a, n) for(int i = a; i<n; i++)
 #define ull unsigned long long
 typedef pair<int, int> pll;
 const double PI = acos(-1.0);
 const double eps = 1e-;
 const int mod = 1e9+;
 const int inf = ;
 const int dir[][] = { {-, }, {, }, {, -}, {, } };
 const int maxn = 1e6+;
 int next[maxn], a[maxn], vis[maxn], used[maxn];
 char s[maxn];
 void get_next() {
     int len = strlen(s);
     int i = , j = -;
     next[] = -;
     while(i<len) {
         if(j==- || s[i] == s[j]) {
             i++, j++;
             next[i] = j;
         } else {
             j = next[j];
         }
     }
     int pos = next[len];
     while(pos != -) {
         vis[pos] = ;
         pos = next[pos];
     }
     return ;
 }
 int main()
 {
     int n, m;
     cin>>n>>m;
     scanf("%s", s);
     int len = strlen(s);
     get_next();
     for(int i = ; i<=m; i++) {
         scanf("%d", &a[i]);
     }
     sort(a+, a+m+);
     int flag = ;
     for(int i = ; i<=m; i++) {
         if(i ==  || a[i]-a[i-]>len) {
             for(int j = a[i]; j<len+a[i]; j++) {
                 used[j] = ;
             }
         } else {
             if(vis[len+a[i-]-a[i]]) {
                 for(int j = a[i-]+len; j<len+a[i]; j++) {
                     used[j] = ;
                 }
             } else {
                 flag = ;
                 break;
             }
         }
     }
     if(flag) {
         puts("");
         return ;
     }
     ll ans = ;
     for(int i = ; i<=n; i++) {
         if(!used[i]) {
             ans = (ans*)%mod;
         }
     }
     cout<<ans<<endl;
     return ;
 }