Submission #401093

#	Time	Username	Problem	Language	Result	Execution time	Memory
401093		cpp219	Power Plant (JOI20_power)	C++14	100 / 100	167 ms	27520 KiB

power

#pragma GCC optimization "O2"
#pragma GCC optimization "unroll-loop"
#pragma GCC target ("avx2")

#include <bits/stdc++.h>
#define ll int
#define ld long double
#define fs first
#define sc second
using namespace std;
const ll N = 2e5 + 6;
const ll Log2 = 19;
const ll inf = 1e9 + 7;
typedef pair<ll,ll> LL;
string s;
ll n,x,y,a[N],mx[N],ans = 1;
vector<ll> g[N];

void DFS(ll u,ll p){
    mx[u] = a[u];
    for (auto i : g[u]) if (i != p) DFS(i,u);
    ll cur = -a[u],mxchild = 0;
    for (auto i : g[u]) if (mx[i] > 0 && i != p)
        cur += mx[i],mxchild = max(mxchild,mx[i]);
    mx[u] = max(mx[u],cur);
    ans = max(ans,max(mx[u],mxchild + a[u]));
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    #define task "tst"
    if (fopen(task".inp", "r")){
        freopen(task".inp", "r", stdin);
        //freopen(task".out", "w", stdout);
    }
    cin>>n;
    for (ll i = 1;i < n;i++){
        cin>>x>>y;
        g[x].push_back(y); g[y].push_back(x);
    }
    cin>>s;
    for (ll i = 0;i < n;i++) a[i + 1] = s[i] - '0'; DFS(1,0);
    //cout<<mx[3]; return 0;
    cout<<ans;
}

Compilation message (stderr)

power.cpp:1: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    1 | #pragma GCC optimization "O2"
      | 
power.cpp:2: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    2 | #pragma GCC optimization "unroll-loop"
      | 
power.cpp: In function 'int main()':
power.cpp:43:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
   43 |     for (ll i = 0;i < n;i++) a[i + 1] = s[i] - '0'; DFS(1,0);
      |     ^~~
power.cpp:43:53: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   43 |     for (ll i = 0;i < n;i++) a[i + 1] = s[i] - '0'; DFS(1,0);
      |                                                     ^~~
power.cpp:34:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   34 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 41 / 41
• Subtask 3: 53 / 53