三个不同,三个叶子,分治解决。
时间复杂度O(n*log m)
#include <bits/stdc++.h> #include <unordered_map> using namespace std; typedef long long ll; typedef unsigned long long ull; #ifdef LOCAL #define debug(x) cout << "[" __FUNCTION__ ": " #x " = " << (x) << "]\n" #define TIME cout << "RuningTime: " << clock() << "ms\n", 0 #else #define TIME 0 #endif #define hash_ 1000000009 #define gc p1 == p2 && (p2 = (p1 = buf) + fread(buf, 1, 1000000, stdin), p1 == p2) ? EOF : *p1++; inline int read() { static char buf[1000000], *p1 = buf, *p2 = buf; int x = false; char ch = gc; bool sgn = false; while (ch != '-' && (ch < '0' || ch > '9')) ch = gc; if (ch == '-') sgn = true, ch = gc; while (ch >= '0'&& ch <= '9') x = (x << 1) + (x << 3) + (ch ^ 48), ch = gc; return sgn ? -x : x; } template<class T> T gcd(T a, T b) { return b == 0 ? a : gcd(b, a % b); }; ll fpow(ll a, ll b, int mod) { ll res = 1; for (; b > 0; b >>= 1) { if (b & 1) res = res * a % mod; a = a * a % mod; } return res; } const int mod = 1e9 + 7; const int INF = 0x3f3f3f3f; const ll LINF = 0x3f3f3f3f3f3f3f3f; const int N = 1e5 + 10; char s[N]; char t[N]; int off; struct StringHash { ull h[N], w[N], base; void Init(ll b, ll m) { h[0] = 0, w[0] = 1, base = b; } void Add(char* s) { int len = strlen(s + 1); for (int i = 1; i <= len; i++) h[i] = h[i - 1] * base + s[i], w[i] = w[i - 1] * base; } ull Get(int l, int r) { if (l > r) return 0; return h[r] - h[l - 1] * w[r - l + 1]; } }ha1, ha2; int cnt; void solve(int L, int R) { if (cnt > 4) return; if (L == R) { cnt++; return; } int mid = (L + R >> 1); if (ha1.Get(L + off, mid + off) != ha2.Get(L, mid)) solve(L, mid); if (ha1.Get(mid + 1 + off, R + off) != ha2.Get(mid + 1, R)) solve(mid + 1, R); } int main() { #ifdef LOCAL freopen("E:/input.txt", "r", stdin); #endif int T; cin >> T; ha1.Init(233, 1e9 + 7); ha2.Init(233, 1e9 + 7); while (T--) { scanf("%s", s + 1); scanf("%s", t + 1); int n = strlen(s + 1), m = strlen(t + 1); ha1.Add(s), ha2.Add(t); int ans = 0; for (int i = 1; i <= n - m + 1; i++) { cnt = 0; off = i - 1; solve(1, m); ans += cnt < 4; } cout << ans << endl; } return TIME; }