oj.uz

답안 #77010

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
77010 2018-09-20T04:31:08 Z samuelfgs96 회문 (APIO14_palindrome) C++11
73 / 100
 1000 ms 112056 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();
	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> t;
	int n;
	rmq () { }
	rmq(int n):t(2*n, -0x3f3f3f3f), n(n) {}
	
	void update(int p, int v) {
		for (t[p+=n] = v; p > 1; p >>= 1) {
			t[p>>1]=max(t[p], t[p^1]);
		}
	}
	
	int query(int l, int r) {
		int ans = -0x3f3f3f3f;
		for (l += n, r += n; l < r; l >>= 1, r >>=1) {
			if (l&1) ans = max(ans, t[l++]);
			if (r&1) ans = max(ans, t[--r]);
		}
		return ans;
	}
} st;

ll ans = 0;
void solve (int u, ll len) {
	len += t[u].len();
	if (len) {
		int l = comeco[u];
		int r = comeco[u] + 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+1);
			if (ret >= mid) {
				ans = mid;
				lo = mid+1;
			} else hi = mid-1;
		}
		::ans = max(::ans, sz[u] * ll(ans));
	}
	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);
	for (int i = 0; i <= 2*n; i++) st.update(i, L[i]);	
	dfs(0, 0);
	memset (pai, -1, sizeof pai);
	solve(0, 0);
	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 44 ms 44408 KB Output is correct
2 Correct 40 ms 44512 KB Output is correct
3 Correct 41 ms 44512 KB Output is correct
4 Correct 50 ms 44512 KB Output is correct
5 Correct 43 ms 44532 KB Output is correct
6 Correct 41 ms 44600 KB Output is correct
7 Correct 41 ms 44620 KB Output is correct
8 Correct 48 ms 44652 KB Output is correct
9 Correct 41 ms 44656 KB Output is correct
10 Correct 42 ms 44660 KB Output is correct
11 Correct 41 ms 44680 KB Output is correct
12 Correct 42 ms 44688 KB Output is correct
13 Correct 41 ms 44692 KB Output is correct
14 Correct 40 ms 44692 KB Output is correct
15 Correct 44 ms 44840 KB Output is correct
16 Correct 45 ms 44840 KB Output is correct
17 Correct 41 ms 44840 KB Output is correct
18 Correct 41 ms 44840 KB Output is correct
19 Correct 43 ms 44840 KB Output is correct
20 Correct 48 ms 44840 KB Output is correct
21 Correct 43 ms 44840 KB Output is correct
22 Correct 43 ms 44840 KB Output is correct
23 Correct 42 ms 44840 KB Output is correct
24 Correct 41 ms 44840 KB Output is correct
25 Correct 41 ms 44840 KB Output is correct
26 Correct 48 ms 44840 KB Output is correct
27 Correct 41 ms 44840 KB Output is correct
28 Correct 40 ms 44840 KB Output is correct
29 Correct 45 ms 44840 KB Output is correct
30 Correct 41 ms 44840 KB Output is correct
31 Correct 40 ms 44840 KB Output is correct
32 Correct 41 ms 44840 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 41 ms 44928 KB Output is correct
2 Correct 41 ms 44964 KB Output is correct
3 Correct 42 ms 44968 KB Output is correct
4 Correct 43 ms 44976 KB Output is correct
5 Correct 42 ms 45004 KB Output is correct
6 Correct 42 ms 45004 KB Output is correct
7 Correct 42 ms 45004 KB Output is correct
8 Correct 41 ms 45004 KB Output is correct
9 Correct 41 ms 45004 KB Output is correct
10 Correct 42 ms 45004 KB Output is correct
11 Correct 43 ms 45064 KB Output is correct
12 Correct 45 ms 45068 KB Output is correct

Subtask #3
24.0 / 24.0

# 결과 실행 시간 메모리 Grader output
1 Correct 55 ms 46736 KB Output is correct
2 Correct 57 ms 46736 KB Output is correct
3 Correct 56 ms 47144 KB Output is correct
4 Correct 53 ms 47144 KB Output is correct
5 Correct 67 ms 47144 KB Output is correct
6 Correct 65 ms 47144 KB Output is correct
7 Correct 57 ms 47144 KB Output is correct
8 Correct 61 ms 47144 KB Output is correct
9 Correct 62 ms 47144 KB Output is correct
10 Correct 68 ms 47144 KB Output is correct

Subtask #4
26.0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 270 ms 62980 KB Output is correct
2 Correct 285 ms 62980 KB Output is correct
3 Correct 222 ms 67084 KB Output is correct
4 Correct 231 ms 67084 KB Output is correct
5 Correct 399 ms 67084 KB Output is correct
6 Correct 360 ms 67084 KB Output is correct
7 Correct 308 ms 67084 KB Output is correct
8 Correct 423 ms 67084 KB Output is correct
9 Correct 397 ms 67084 KB Output is correct
10 Correct 464 ms 67084 KB Output is correct

Subtask #5
0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Correct 825 ms 99536 KB Output is correct
2 Correct 923 ms 99536 KB Output is correct
3 Correct 643 ms 112056 KB Output is correct
4 Correct 727 ms 112056 KB Output is correct
5 Execution timed out 1078 ms 112056 KB Time limit exceeded
6 Halted 0 ms 0 KB -