oj.uz

답안 #77014

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
77014 2018-09-20T04:34:51 Z samuelfgs96 회문 (APIO14_palindrome) C++11
73 / 100
 297 ms 132096 KB 
#include <bits/stdc++.h>
 
#define fi first
#define se second
using namespace std;
typedef long long ll;
const int N = 312345;
string s;
int at;
struct No {
    int L, R, p, suff;
    map <char, int> f;
    No() {}
    No(int l, int r, int P) : L(l), R(r), p(P) {}
    inline int len () {
        return R-L+1;
    }
    inline char operator[] (int i) {
        return s[L + i];
    }
    void print() {
        for (int i = 0; i < len(); i++) printf("%c", (*this)[i]);
    }
} t[2*N];
int novo (int L, int R, int p) {
    t[at] = No (L, R, p);
    at++;
    return at-1;
}
void build_suffix_tree () {
    novo (0, -1, -1); //criando raiz
    
    s += "$";
    int i = 0, cn = 0, cd = 0, ns = 0;
    int n = s.size();
    for (int j = 0; j < s.size(); j++) {
        for (; i <= j; i++) {
            if (t[cn].len() == cd ? t[cn].f.count(s[j]) : t[cn][cd] == s[j]) {//CASO 1
                if (t[cn].len() == cd) {
                    cd = 0;
                    cn = t[cn].f[s[j]];
                }
                cd++;
                break;
            } else if (t[cn].len() == cd) {//CASO 2
                t[cn].f[s[j]] = novo(j, n-1, cn);
                if (cn) {
                    cn = t[cn].suff;
                    cd = t[cn].len();
                }
            } else {//CASO 3 (precisa criar o suffix link)
                //quebrar a aresta
                int mid = novo (t[cn].L, t[cn].L + cd - 1, t[cn].p);
                t[t[mid].p].f[t[mid][0]] = mid;
                t[mid].f[s[j]] = novo (j, n-1, mid);
                t[mid].f[t[cn][cd]] = cn;
                t[cn].p = mid;
                t[cn].L += cd;
                if (ns) t[ns].suff = mid;
                //achar o suffix link de mid
                cn = t[mid].p;
                int g;
                if (cn) {
                    cn = t[cn].suff;
                    g = j - cd;
                } else g = i+1;
                while (g < j && g + t[t[cn].f[s[g]]].len() <= j) {
                    cn = t[cn].f[s[g]];
                    g += t[cn].len();
                }
                if (g == j) {
                    t[mid].suff = cn;
                    cd = t[cn].len();
                    ns = 0;
                } else { // g < j
                    ns = mid;
                    cn = t[cn].f[s[g]];
                    cd = j - g;
                }
            }
        }
    }
}
int L[N*2]; //LPS Length Array
void findLongestPalindromicString() {
	string text = s;
	int N = text.size();
    if(N == 0)
        return;
    N = 2*N + 1; //Position count
    L[0] = 0;
    L[1] = 1;
    int C = 1; //centerPosition 
    int R = 2; //centerRightPosition
    int i = 0; //currentRightPosition
    int iMirror; //currentLeftPosition
    int maxLPSLength = 0;
    int maxLPSCenterPosition = 0;
    int start = -1;
    int end = -1;
    int diff = -1;
     
    //Uncomment it to print LPS Length array
    //printf("%d %d ", L[0], L[1]);
    for (i = 2; i < N; i++) 
    {
        //get currentLeftPosition iMirror for currentRightPosition i
        iMirror  = 2*C-i;
        L[i] = 0;
        diff = R - i;
        //If currentRightPosition i is within centerRightPosition R
        if(diff > 0)
            L[i] = min(L[iMirror], diff);
 
        //Attempt to expand palindrome centered at currentRightPosition i
        //Here for odd positions, we compare characters and 
        //if match then increment LPS Length by ONE
        //If even position, we just increment LPS by ONE without 
        //any character comparison
        while ( ((i + L[i]) < N && (i - L[i]) > 0) && 
            ( ((i + L[i] + 1) % 2 == 0) || 
            (text[(i + L[i] + 1)/2] == text[(i - L[i] - 1)/2] )))
        {
            L[i]++;
        }
 
        if(L[i] > maxLPSLength)  // Track maxLPSLength
        {
            maxLPSLength = L[i];
            maxLPSCenterPosition = i;
        }
 
        //If palindrome centered at currentRightPosition i 
        //expand beyond centerRightPosition R,
        //adjust centerPosition C based on expanded palindrome.
        if (i + L[i] > R) 
        {
            C = i;
            R = i + L[i];
        }
        //Uncomment it to print LPS Length array
        //printf("%d ", L[i]);
    }
    //printf("\n");
    start = (maxLPSCenterPosition - maxLPSLength)/2;
    end = start + maxLPSLength - 1;
}
int pos[N], pai[N*2], sz[N*2], ac[N*2], comeco[N];
void dfs (int u, int len) {
	len += t[u].len();
	ac[u] = len;
	if (t[u].R + 1 == (int)s.size()) {
		pos[int(s.size()) - len] = u;
		comeco[u] = int(s.size()) - len;
		sz[u] = 1;
		return ;
	}
	for (auto v : t[u].f) {
		dfs(v.se, len);
		sz[u] += sz[v.se];
		comeco[u] = comeco[v.se];
	}
}
const int LN = 20;
int _log[2*N+10];
struct rmq {
	int table[N*2][LN], n;
	rmq () { }
	rmq (int n) : n(n) {
		for (int i = 0; i < n; i++) {
			table[i][0] = L[i];
		}
		for (int j = 1; (1<<j) <= n; j++)
		for (int i = 0; i + (1<<j) <= n; i++)
			table[i][j] = max(table[i][j-1], table[i+(1<<(j-1))][j-1]);
	}
	int query (int l, int r) {
		int sz = r - l + 1;
		int lg = _log[sz];
		return max(table[l][lg], table[r - (1<<lg) + 1][lg]);
	}
} st;

ll ans = 0;
void solve (int u, ll len) {
	for (auto v : t[u].f)
		solve(v.se, len);
}
int main (void) {
	_log[1] = 0;
	for (int i = 2; i < 2*N; i++) {
		_log[i] = _log[i-1];
		if ( (1<<(_log[i] + 1)) == i) _log[i]++;
	}
	cin >> s;
	int n = s.size();
	build_suffix_tree();
	findLongestPalindromicString();
	st = rmq(2*n+1);
	dfs(0, 0);
	memset (pai, -1, sizeof pai);
	for (int i = 1; i < at; i++) {
		int len = ac[i];
		int l = comeco[i];
		int r = comeco[i] + len - 1;
		//find longest palindrome in l r
		l = l * 2;
		r = r * 2 + 2;
		int lo = 0, hi = r-l+1, ans = 0;
		while (lo <= hi) {
			int mid = (lo + hi) / 2;
			int ql = l + mid, qr = r - mid;
			if (ql > qr) {
				hi = mid-1;
				continue;
			}
			int ret = st.query(ql, qr);
			if (ret >= mid) {
				ans = mid;
				lo = mid+1;
			} else hi = mid-1;
		}
		::ans = max(::ans, sz[i] * ll(ans));
	}

	cout << ans << endl;
	return 0;
}

Compilation message

palindrome.cpp: In function 'void build_suffix_tree()':
palindrome.cpp:36:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int j = 0; j < s.size(); j++) {
                     ~~^~~~~~~~~~
palindrome.cpp: In function 'void findLongestPalindromicString()':
palindrome.cpp:100:9: warning: variable 'end' set but not used [-Wunused-but-set-variable]
     int end = -1;
         ^~~
palindrome.cpp: In function 'int novo(int, int, int)':
palindrome.cpp:10:8: warning: '<anonymous>.No::suff' is used uninitialized in this function [-Wuninitialized]
 struct No {
        ^~

Subtask #1
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 94 ms 93432 KB Output is correct
2 Correct 110 ms 93688 KB Output is correct
3 Correct 98 ms 93688 KB Output is correct
4 Correct 95 ms 93688 KB Output is correct
5 Correct 95 ms 93688 KB Output is correct
6 Correct 93 ms 93688 KB Output is correct
7 Correct 95 ms 93688 KB Output is correct
8 Correct 95 ms 93688 KB Output is correct
9 Correct 94 ms 93688 KB Output is correct
10 Correct 95 ms 93688 KB Output is correct
11 Correct 96 ms 93688 KB Output is correct
12 Correct 98 ms 93688 KB Output is correct
13 Correct 98 ms 93688 KB Output is correct
14 Correct 100 ms 93688 KB Output is correct
15 Correct 101 ms 93688 KB Output is correct
16 Correct 101 ms 93688 KB Output is correct
17 Correct 100 ms 93688 KB Output is correct
18 Correct 96 ms 93688 KB Output is correct
19 Correct 93 ms 93688 KB Output is correct
20 Correct 94 ms 93776 KB Output is correct
21 Correct 96 ms 93776 KB Output is correct
22 Correct 94 ms 93780 KB Output is correct
23 Correct 96 ms 93780 KB Output is correct
24 Correct 96 ms 93780 KB Output is correct
25 Correct 98 ms 93780 KB Output is correct
26 Correct 153 ms 93780 KB Output is correct
27 Correct 98 ms 93780 KB Output is correct
28 Correct 98 ms 93780 KB Output is correct
29 Correct 93 ms 93780 KB Output is correct
30 Correct 97 ms 93780 KB Output is correct
31 Correct 96 ms 93780 KB Output is correct
32 Correct 95 ms 93780 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 98 ms 93920 KB Output is correct
2 Correct 99 ms 93932 KB Output is correct
3 Correct 96 ms 93972 KB Output is correct
4 Correct 100 ms 93972 KB Output is correct
5 Correct 97 ms 93984 KB Output is correct
6 Correct 96 ms 93984 KB Output is correct
7 Correct 102 ms 93984 KB Output is correct
8 Correct 100 ms 93984 KB Output is correct
9 Correct 97 ms 93984 KB Output is correct
10 Correct 99 ms 93984 KB Output is correct
11 Correct 99 ms 93984 KB Output is correct
12 Correct 100 ms 93984 KB Output is correct

Subtask #3
24.0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Correct 107 ms 96764 KB Output is correct
2 Correct 104 ms 96764 KB Output is correct
3 Correct 106 ms 96960 KB Output is correct
4 Correct 112 ms 96960 KB Output is correct
5 Correct 111 ms 96960 KB Output is correct
6 Correct 109 ms 96960 KB Output is correct
7 Correct 108 ms 96960 KB Output is correct
8 Correct 107 ms 96960 KB Output is correct
9 Correct 112 ms 96960 KB Output is correct
10 Correct 118 ms 96960 KB Output is correct

Subtask #4
26.0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 215 ms 124668 KB Output is correct
2 Correct 234 ms 124668 KB Output is correct
3 Correct 184 ms 127100 KB Output is correct
4 Correct 199 ms 127100 KB Output is correct
5 Correct 224 ms 127100 KB Output is correct
6 Correct 221 ms 127100 KB Output is correct
7 Correct 202 ms 127100 KB Output is correct
8 Correct 253 ms 127100 KB Output is correct
9 Correct 236 ms 127100 KB Output is correct
10 Correct 245 ms 127100 KB Output is correct

Subtask #5
0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Runtime error 297 ms 132096 KB Execution killed with signal 9 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -