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POJ 3974 馬拉車

POJ 3974

#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <set>
#include <queue>
#include <map>
#include <sstream>
#include <cstdio>
#include <cstring>
#include <numeric>
#include <cmath>
#include 
<iomanip> #include <deque> #include <bitset> //#include <unordered_set> //#include <unordered_map> #define ll long long #define pii pair<int, int> #define rep(i,a,b) for(ll i=a;i<=b;i++) #define dec(i,a,b) for(ll i=a;i>=b;i--) #define
forn(i, n) for(ll i = 0; i < int(n); i++) using namespace std; int dir[4][2] = { { 1,0 },{ 0,1 } ,{ 0,-1 },{ -1,0 } }; const long long INF = 0x7f7f7f7f7f7f7f7f; const int inf = 0x3f3f3f3f; const double pi = 3.14159265358979323846; const double eps = 1e-6; const int mod = 1e7 + 7; inline ll read() { ll x
= 0; bool f = true; char c = getchar(); while (c < '0' || c > '9') { if (c == '-') f = false; c = getchar(); } while (c >= '0' && c <= '9') x = (x << 1) + (x << 3) + (c ^ 48), c = getchar(); return f ? x : -x; } inline ll gcd(ll m, ll n) { return n == 0 ? m : gcd(n, m % n); } void exgcd(ll A, ll B, ll& x, ll& y) { if (B) exgcd(B, A % B, y, x), y -= A / B * x; else x = 1, y = 0; } bool prime(int x) { if (x < 2) return false; for (int i = 2; i * i <= x; ++i) { if (x % i == 0) return false; } return true; } inline int qpow(int x, ll n) { int r = 1; while (n > 0) { if (n & 1) r = 1ll * r * x % mod; n >>= 1; x = 1ll * x * x % mod; } return r; } string s; int cas; void manacher() { vector<char> ss(2 * s.size() + 1, '#'); vector<int> p(ss.size() + 1); for (int i = 0; i < ss.size(); i++) { if (i % 2 == 0) ss[i] = s[i / 2]; } ss.insert(ss.begin(), '#'); int ans = 0, id = 0, mx = -1; for (int i = 0; i < ss.size(); i++) { if (id + mx > i) p[i] = min(p[id * 2 - i], id + mx - i); while (i - p[i] - 1 >= 0 && i + p[i] + 1 <= ss.size() && ss[i - p[i] - 1] == ss[i + p[i] + 1]) p[i]++; if (id + mx < i + p[i]) id = i, mx = p[i]; ans = max(ans, p[i]); } printf("Case %d: %d\n", ++cas, ans); } int main() { while (cin >> s) { if (s == "END") break; manacher(); } return 0; }