Submission #223450

#	Time	Username	Problem	Language	Result	Execution time	Memory
223450		dantoh000	Lampice (COCI19_lampice)	C++14	73 / 110	5056 ms	9856 KiB

lampice

#include <bits/stdc++.h>
using namespace std;
int n;
vector<int> adjlist[50005];
int ans = 1;
string s;
void maxlpalindrome(vector<char> s){
    //for (auto x : s) printf("%c",x);
    //printf(" processing\n");
    int n = s.size();
    ///For odd-length palindrome
    vector<int> d1(n,0);
    for (int i = 0, l = 0, r = -1; i < n; i++) {
        int k = (i > r) ? 1 : min(d1[l + r - i], r - i + 1);
        while (0 <= i - k && i + k < n && s[i - k] == s[i + k]) {
            k++;
        }
        d1[i] = k--;
        if (i + k > r) {
            l = i - k;
            r = i + k;
        }
    }
    ///For even-length palindromes
    vector<int> d2(n,0);
    for (int i = 0, l = 0, r = -1; i < n; i++) {
        int k = (i > r) ? 0 : min(d2[l + r - i + 1], r - i + 1);
        while (0 <= i - k - 1 && i + k < n && s[i - k - 1] == s[i + k]) {
            k++;
        }
        d2[i] = k--;
        if (i + k > r) {
            l = i - k - 1;
            r = i + k ;
        }
    }
    for (int i = 0; i < n; i++){
        ans = max(ans,max(2*d1[i]-1,2*d2[i]));
    }
}
vector<char> st;
void dfs(int u, int p){
    st.push_back(s[u-1]);
    int k = 0;
    for (auto v : adjlist[u]){
        if (v == p) continue;
        k = 1;
        dfs(v,u);
    }
    if (k == 0) maxlpalindrome(st);
    st.pop_back();
}
int main(){
    scanf("%d",&n);
    cin >> s;
    for (int i = 0; i < n-1; i++){
        int a,b;
        scanf("%d%d",&a,&b);
        adjlist[a].push_back(b);
        adjlist[b].push_back(a);
    }
    for (int i = 1; i <= n; i++){
        if (adjlist[i].size() == 1){
            st.clear();
            dfs(i,-1);
        }
    }
    printf("%d",ans);

}

Compilation message (stderr)

lampice.cpp: In function 'int main()':
lampice.cpp:54:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&n);
     ~~~~~^~~~~~~~~
lampice.cpp:58:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d",&a,&b);
         ~~~~~^~~~~~~~~~~~~~

• Subtask 1: 17 / 17
• Subtask 2: 25 / 25
• Subtask 3: 31 / 31
• Subtask 4: 0 / 37