oj.uz

답안 #77021

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
77021 2018-09-20T05:00:20 Z samuelfgs96 회문 (APIO14_palindrome) C++11
100 / 100
 566 ms 114944 KB 
#include <bits/stdc++.h>
#define pb push_back
#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]);
    }
};
vector <No> t;
int novo (int L, int R, int p) {
	t.pb( 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[2*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 {
	vector <int> table[20];
	int n;
	rmq () { }
	rmq (int n) : n(n) {
		for (int j = 0; j < 20; j++) table[j].resize(n);
		for (int i = 0; i < n; i++) {
			table[0][i] = L[i];
		}
		for (int j = 1; (1<<j) <= n; j++)
		for (int i = 0; i + (1<<j) <= n; i++)
			table[j][i] = max(table[j-1][i], table[j-1][i+(1<<(j-1))]);
	}
	int query (int l, int r) {
		int sz = r - l + 1;
		int lg = _log[sz];
		return max(table[lg][l], table[lg][r - (1<<lg) + 1]);
	}
} 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();
	dfs(0, 0);
	t.clear();
	st = rmq(2*n+1);
	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:37:23: 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:101:9: 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' may be used uninitialized in this function [-Wmaybe-uninitialized]
 struct No {
        ^~

Subtask #1
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 5240 KB Output is correct
2 Correct 7 ms 5408 KB Output is correct
3 Correct 6 ms 5408 KB Output is correct
4 Correct 7 ms 5408 KB Output is correct
5 Correct 7 ms 5464 KB Output is correct
6 Correct 7 ms 5464 KB Output is correct
7 Correct 7 ms 5540 KB Output is correct
8 Correct 6 ms 5540 KB Output is correct
9 Correct 7 ms 5540 KB Output is correct
10 Correct 7 ms 5540 KB Output is correct
11 Correct 7 ms 5540 KB Output is correct
12 Correct 6 ms 5540 KB Output is correct
13 Correct 6 ms 5540 KB Output is correct
14 Correct 7 ms 5540 KB Output is correct
15 Correct 7 ms 5540 KB Output is correct
16 Correct 7 ms 5540 KB Output is correct
17 Correct 9 ms 5540 KB Output is correct
18 Correct 7 ms 5540 KB Output is correct
19 Correct 7 ms 5540 KB Output is correct
20 Correct 7 ms 5600 KB Output is correct
21 Correct 7 ms 5600 KB Output is correct
22 Correct 7 ms 5600 KB Output is correct
23 Correct 7 ms 5600 KB Output is correct
24 Correct 7 ms 5612 KB Output is correct
25 Correct 7 ms 5612 KB Output is correct
26 Correct 7 ms 5612 KB Output is correct
27 Correct 7 ms 5612 KB Output is correct
28 Correct 7 ms 5612 KB Output is correct
29 Correct 7 ms 5612 KB Output is correct
30 Correct 7 ms 5612 KB Output is correct
31 Correct 7 ms 5612 KB Output is correct
32 Correct 7 ms 5612 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 7 ms 5884 KB Output is correct
2 Correct 10 ms 5884 KB Output is correct
3 Correct 7 ms 5884 KB Output is correct
4 Correct 7 ms 5884 KB Output is correct
5 Correct 7 ms 5888 KB Output is correct
6 Correct 7 ms 5888 KB Output is correct
7 Correct 7 ms 5888 KB Output is correct
8 Correct 8 ms 5888 KB Output is correct
9 Correct 7 ms 5888 KB Output is correct
10 Correct 7 ms 5888 KB Output is correct
11 Correct 8 ms 5888 KB Output is correct
12 Correct 7 ms 5888 KB Output is correct

Subtask #3
24.0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Correct 15 ms 8936 KB Output is correct
2 Correct 16 ms 8936 KB Output is correct
3 Correct 15 ms 9196 KB Output is correct
4 Correct 16 ms 9196 KB Output is correct
5 Correct 15 ms 9196 KB Output is correct
6 Correct 17 ms 9196 KB Output is correct
7 Correct 15 ms 9196 KB Output is correct
8 Correct 15 ms 9196 KB Output is correct
9 Correct 16 ms 9196 KB Output is correct
10 Correct 18 ms 9196 KB Output is correct

Subtask #4
26.0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 118 ms 39768 KB Output is correct
2 Correct 110 ms 39768 KB Output is correct
3 Correct 101 ms 42180 KB Output is correct
4 Correct 95 ms 42180 KB Output is correct
5 Correct 125 ms 42180 KB Output is correct
6 Correct 119 ms 42180 KB Output is correct
7 Correct 92 ms 42180 KB Output is correct
8 Correct 142 ms 42180 KB Output is correct
9 Correct 139 ms 42180 KB Output is correct
10 Correct 141 ms 42180 KB Output is correct

Subtask #5
27.0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Correct 385 ms 108028 KB Output is correct
2 Correct 352 ms 108028 KB Output is correct
3 Correct 324 ms 114944 KB Output is correct
4 Correct 320 ms 114944 KB Output is correct
5 Correct 368 ms 114944 KB Output is correct
6 Correct 366 ms 114944 KB Output is correct
7 Correct 362 ms 114944 KB Output is correct
8 Correct 549 ms 114944 KB Output is correct
9 Correct 566 ms 114944 KB Output is correct
10 Correct 457 ms 114944 KB Output is correct
11 Correct 416 ms 114944 KB Output is correct
12 Correct 510 ms 114944 KB Output is correct