#include <bits/stdc++.h> using namespace std; #define int long long #define FOR(I, L, R) for(int I(L) ; I <= (int)R ; ++I) #define FOD(I, R, L) for(int I(R) ; I >= (int)L ; --I) #define FOA(I, A) for(auto &I : A) #define print(A,L,R) FOR(OK, L, R){if(A[OK]<=-oo / 10||A[OK]>=oo)cout<<"- ";else cout<<A[OK]<<' ';}cout<<'\n'; #define prints(A) FOA(OK, A){cout<<OK<<' ';}cout << '\n'; #define printz(A,L,R) FOR(OK, 0, L){FOR(KO, 1, R){if(A[OK][KO]>-oo&&A[OK][KO]<oo)cout<<A[OK][KO]<<' ';else cout << "- ";} cout << '\n';}cout << '\n'; #define fs first #define sd second #define ii pair<int,int> #define iii pair<int, ii> #define all(A) A.begin(), A.end() #define quickly ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); #define FILE "FILE" const int N = 2e5 + 5; const int mod = 1e9 + 7; const int oo = 1e18; struct Modint{ int x; Modint(){x = 0;} Modint(int _x){ x = (_x % mod + mod) % mod; } inline Modint operator + (const Modint &other) const{ return (x + other.x) % mod; } inline Modint operator - (const Modint &other) const{ return (x - other.x + mod) % mod; } inline Modint operator * (const Modint &other) const{ return (1LL * x * other.x) % mod; } inline void operator += (const Modint &other){ *this = *this + other; } inline void operator -= (const Modint &other){ *this = *this - other; } inline void operator *= (const Modint &other){ *this = *this * other; } friend ostream& operator << (ostream& os, const Modint &t){ return os << t.x; } }; int n; int dp[3][N]; string s; vector<int> g[N]; void DFS(int u, int par){ dp[0][u] = 0; if(s[u] == '1'){ dp[1][u] = 1; } int sum = 0, add = 0; int w = (s[u] == '1'); FOA(v, g[u]){ if(v == par){ continue; } DFS(v, u); sum += max(0LL, dp[1][v]); } FOA(v, g[u]){ if(v == par){ continue; } dp[1][u] = max(dp[1][u], sum - w); dp[2][u] = max(dp[2][u], dp[1][v] + w); } } signed main(){ quickly if(fopen(FILE".inp", "r")){ freopen(FILE".inp", "r", stdin); freopen(FILE".out", "w", stdout); } cin >> n; FOR(i, 1, n - 1){ int u, v; cin >> u >> v; g[u].push_back(v); g[v].push_back(u); } cin >> s; s = " " + s; FOR(i, 1, n){ dp[0][i] = dp[1][i] = dp[2][i] = -oo; } DFS(1, -1); int ans = 0; FOR(i, 1, n){ ans = max({ans, dp[1][i], dp[2][i]}); } cout << ans; }

power.cpp: In function 'int main()':
power.cpp:77:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |                 freopen(FILE".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
power.cpp:78:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |                 freopen(FILE".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~