제출 #755877

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
755877		TranLoc	Harbingers (CEOI09_harbingers)	C++17	50 / 100	142 ms	20116 KiB

harbingers

#include <bits/stdc++.h>
#define X first
#define Y second
const int N = 100005;
const long long INF = (long long)1e18;
using namespace std;
typedef pair<int, int> Line;
struct operation {
    int pos, top;
    Line overwrite;
    operation(int _p, int _t, Line _o) {
        pos = _p; top = _t; overwrite = _o;
    }
};
vector<operation> undoLst;
Line lines[N];
int n, top;
long long eval(Line line, long long x) {return line.X * x + line.Y;}
bool bad(Line a, Line b, Line c)
    {return (double)(b.Y - a.Y) / (a.X - b.X) >= (double)(c.Y - a.Y) / (a.X - c.X);}
long long getMin(long long coord) {
    int l = 0, r = top - 1; long long ans = eval(lines[l], coord);
    while (l < r) {
        int mid = l + r >> 1;
        long long x = eval(lines[mid], coord);
        long long y = eval(lines[mid + 1], coord);
        if (x > y) l = mid + 1; else r = mid;
        ans = min(ans, min(x, y));
    }
    return ans;
}
bool insertLine(Line newLine) {
    int l = 1, r = top - 1, k = top;
    while (l <= r) {
        int mid = l + r >> 1;
        if (bad(lines[mid - 1], lines[mid], newLine)) {
            k = mid; r = mid - 1;
        }
        else l = mid + 1;
    }
    undoLst.push_back(operation(k, top, lines[k]));
    top = k + 1;
    lines[k] = newLine;
    return 1;
}
void undo() {
    operation ope = undoLst.back(); undoLst.pop_back();
    top = ope.top; lines[ope.pos] = ope.overwrite;
}
long long f[N], S[N], V[N], d[N];
vector<Line> a[N];
void dfs(int u, int par) {
    if (u > 1)
        f[u] = getMin(V[u]) + S[u] + V[u] * d[u];
    insertLine(make_pair(-d[u], f[u]));
    for (vector<Line>::iterator it = a[u].begin(); it != a[u].end(); ++it) {
        int v = it->X;
        int uv = it->Y;
        if (v == par) continue;
        d[v] = d[u] + uv;
        dfs(v, u);
    }
    undo();
}
int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> n;
    int u, v, c;
    for (int i = 1; i < n; ++i) {
        cin >> u >> v >> c;
        a[u].push_back(make_pair(v, c));
        a[v].push_back(make_pair(u, c));
    }
    for (int i = 2; i <= n; ++i) cin >> S[i] >> V[i];
    dfs(1, 0);
    for (int i = 2; i <= n; ++i) cout << f[i] << ' ';
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

harbingers.cpp: In function 'long long int getMin(long long int)':
harbingers.cpp:24:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   24 |         int mid = l + r >> 1;
      |                   ~~^~~
harbingers.cpp: In function 'bool insertLine(Line)':
harbingers.cpp:35:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   35 |         int mid = l + r >> 1;
      |                   ~~^~~

• Subtask 1: 50 / 100