Submission #632901

#	Time	Username	Problem	Language	Result	Execution time	Memory
632901		racsosabe	Savez (COCI15_savez)	C++14	0 / 120	108 ms	31652 KiB

savez

#include<bits/stdc++.h>
using namespace::std;

const int B[] = {311, 257};
const int MOD = 1e9 + 7;
const int N = 2000000 + 5;

int mul(int a, int b){
	return (1ll * a * b) % MOD;
}

int pow_mod(int a, int b){
	int r = 1;
	while(b){
		if(b & 1) r = mul(r, a);
		a = mul(a, a);
		b >>= 1;
	}
	return r;
}

int n;
char s[N];
int pot[2][N];
int poti[2][N];
int prefix[2][N];
map<pair<int, int>, int> best;

void init(){
	for(int id = 0; id < 2; id++){
		pot[id][0] = 1;
		for(int i = 1; i < N; i++) pot[id][i] = mul(pot[id][i - 1], B[id]);
		poti[id][N - 1] = pow_mod(pot[id][N - 1], MOD - 2);
		for(int i = N - 2; i >= 0; i--) poti[id][i] = mul(poti[id][i + 1], B[id]);
	}
}

bool check(int l, int len){
	for(int id = 0; id < 2; id++){
		int L = prefix[id][l];
		int R = mul((prefix[id][len] + MOD - prefix[id][len - l]), poti[id][len - l]);
		if(L != R) return false;
	}
	return true;
}

int main(){
	init();
	scanf("%d", &n);
	for(int i = 1; i <= n; i++){
		scanf("%s", s + 1);
		int len = strlen(s + 1);
		for(int id = 0; id < 2; id++)
		for(int j = 1; j <= len; j++) prefix[id][j] = (prefix[id][j - 1] + mul(pot[id][j], s[j])) % MOD;
		for(int l = 1; l <= len; l++){
			if(check(l, len)){
				int cur = 1 + (best.count(make_pair(prefix[0][l], prefix[1][l])) ? best[make_pair(prefix[0][l], prefix[1][l])] : 0);
				best[make_pair(prefix[0][len], prefix[1][len])] = cur;
			}
		}
	}
	int ans = 0;
	for(auto e : best){
		if(ans < e.second) ans = e.second;
	}
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

savez.cpp: In function 'int main()':
savez.cpp:49:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |  scanf("%d", &n);
      |  ~~~~~^~~~~~~~~~
savez.cpp:51:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |   scanf("%s", s + 1);
      |   ~~~~~^~~~~~~~~~~~~

• Subtask 1: 0 / 12
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