Submission #74772634

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Source Code Expand

#include <bits/stdc++.h>
using ull = unsigned long long int;
using ll = long long int;
using lll = __int128;
using namespace std;
const int mod = 1e9 + 7;
int d[4][2] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
inline string sread() {
    string s;
    char ch = getchar();
    // 跳过空白字符
    while (ch == ' ' || ch == '\n' || ch == '\r') ch = getchar();
    // 读取非空白字符
    while (ch != ' ' && ch != '\n' && ch != '\r' && ch != EOF) {
        s += ch;
        ch = getchar();
    }
    return s;
}
ll read(){
    ll k = 0,f = 1;
    char c = getchar();
    while(c < '0' || c > '9')
    {
        if(c == '-')f = -1;
        c = getchar();
    }
    while(c >= '0' && c <= '9')k = k * 10 + c - '0',c = getchar();
    return k * f; // 别忘记标记的负数要乘进去
}
// 调用时用 n = in();
void print(ll x){
    if(x < 0)putchar('-'),x = -x;
    if(x < 10)putchar(x + '0');
    else print(x / 10),putchar(x % 10 + '0');
}
// 直接调用 out(n) 就行了
ll ksm(ll base, ll e){
    ll res = 1;
    while(e){
        if(e & 1){
            res = res * base % mod;
        }
        base = base * base % mod;
        e >>= 1;
    }
    return res;
}//ksm板子
vector<vector<ll>> matrix_mul (vector<vector<ll>>& a, vector<vector<ll>>& b) {
    int l1 = a.size(), l2 = b[0].size();
    vector<vector<ll>>res(l1, vector<ll>(l2, 0));
    for(int i = 0; i < l1; i++){
        for(int k = 0; k < a[0].size(); k++){
            if(a[i][k]){
                for(int j = 0; j < l2; j++){
                    res[i][j] = (res[i][j] + a[i][k] * b[k][j]);
                }
            }
        }
    }
    return res;
}// 矩阵a * 矩阵b(矩阵乘法)
void Solve(){
    int n = read();
    vector<vector<int>>g(n + 1);
    for(int i = 2; i <= n; i++){
        int p = read();
        g[p].push_back(i);
        g[i].push_back(p);
    }
    vector<ll>w(n + 1);
    for(int i = 1; i <= n; i++){
        w[i] = read();
    }
    vector<ll>S(n + 1, 0);
    ll ans = 0;
    auto dfs = [&](auto && self, int cur, int fa) -> void{
        S[cur] = w[cur];
        vector<int>c;
        for(auto s : g[cur]){
            if(s == fa)continue;
            c.push_back(s);
            self(self, s, cur);
            S[cur] += S[s];
        }
        if(c.size() > 1){
            ll mx = LLONG_MIN, mn = LLONG_MAX;
            for(int t : c){
                mx = max(mx, S[t]);
                mn = min(mn, S[t]);
            }
            ans = max(ans, mx - mn);
        }
    };
    dfs(dfs, 1, 0);
    cout << ans << '\n';
}
signed main(){
    int T = 1;
    while(T--){
        Solve();
    }
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function 'std::vector<std::vector<long long int> > matrix_mul(std::vector<std::vector<long long int> >&, std::vector<std::vector<long long int> >&)':
./Main.cpp:53:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |         for(int k = 0; k < a[0].size(); k++){
      |                        ~~^~~~~~~~~~~~~

Judge Result