Submission #1093049
Source Code Expand
#include <stdio.h> #include <algorithm> #include <vector> #include <stdlib.h> using LL = long long ; const int kN = 100000 + 5; int n; std::vector<int> edges[kN]; LL a[kN]; void bad() { puts("NO"); exit(0); } LL dfs(int u, int fa) { if (edges[u].size() == 1) return a[u]; LL sum = 0, vmax = 0; for (int v : edges[u]) if (v != fa) { LL cnt = dfs(v, u); sum += cnt; vmax = std::max(vmax, cnt); } LL up = 0, pair = 0; if (vmax * 2 > sum) { up = vmax - (sum - vmax); sum -= up; } pair += sum / 2; up += sum & 1; if (up + 2 * pair < a[u] || up + pair > a[u]) { bad(); } do { LL tmp = a[u] - up - pair; up += tmp * 2; pair -= tmp; } while (false); return up; } int main() { scanf("%d", &n); for (int i = 0; i < n; ++ i) scanf("%lld", a + i); for (int i = 0; i < n - 1; ++ i) { int a, b; scanf("%d%d", &a, &b); a --; b --; edges[a].emplace_back(b); edges[b].emplace_back(a); } if (n == 2) { puts(a[0] == a[1] ? "YES" : "NO"); return 0; } int root = 0; for (int i = 0; i < n; ++ i) if (edges[i].size() > 1) root = i; puts(0 == dfs(root, -1) ? "YES" : "NO"); }
Submission Info
Submission Time | |
---|---|
Task | C - Cleaning |
User | Nero |
Language | C++14 (GCC 5.4.1) |
Score | 700 |
Code Size | 1338 Byte |
Status | AC |
Exec Time | 60 ms |
Memory | 13568 KB |
Compile Error
./Main.cpp: In function ‘int main()’: ./Main.cpp:47:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ ./Main.cpp:48:54: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (int i = 0; i < n; ++ i) scanf("%lld", a + i); ^ ./Main.cpp:51:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &b); a --; b --; ^
Judge Result
Set Name | Sample | All | ||||
---|---|---|---|---|---|---|
Score / Max Score | 0 / 0 | 700 / 700 | ||||
Status |
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Set Name | Test Cases |
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Sample | sample1.txt, sample2.txt, sample3.txt |
All | sample1.txt, sample2.txt, sample3.txt, in1.txt, in10.txt, in11.txt, in12.txt, in13.txt, in14.txt, in15.txt, in16.txt, in17.txt, in18.txt, in19.txt, in2.txt, in20.txt, in21.txt, in22.txt, in23.txt, in24.txt, in25.txt, in26.txt, in27.txt, in28.txt, in29.txt, in3.txt, in30.txt, in31.txt, in32.txt, in33.txt, in34.txt, in35.txt, in36.txt, in37.txt, in38.txt, in39.txt, in4.txt, in40.txt, in41.txt, in42.txt, in43.txt, in44.txt, in45.txt, in5.txt, in6.txt, in7.txt, in8.txt, in9.txt |
Case Name | Status | Exec Time | Memory |
---|---|---|---|
in1.txt | AC | 52 ms | 6528 KB |
in10.txt | AC | 53 ms | 6656 KB |
in11.txt | AC | 60 ms | 12416 KB |
in12.txt | AC | 59 ms | 11776 KB |
in13.txt | AC | 55 ms | 12800 KB |
in14.txt | AC | 57 ms | 13568 KB |
in15.txt | AC | 5 ms | 2560 KB |
in16.txt | AC | 5 ms | 2560 KB |
in17.txt | AC | 5 ms | 2560 KB |
in18.txt | AC | 5 ms | 2560 KB |
in19.txt | AC | 51 ms | 6528 KB |
in2.txt | AC | 52 ms | 6656 KB |
in20.txt | AC | 49 ms | 6656 KB |
in21.txt | AC | 49 ms | 6528 KB |
in22.txt | AC | 50 ms | 6528 KB |
in23.txt | AC | 51 ms | 6528 KB |
in24.txt | AC | 50 ms | 6656 KB |
in25.txt | AC | 5 ms | 2560 KB |
in26.txt | AC | 51 ms | 6528 KB |
in27.txt | AC | 51 ms | 6656 KB |
in28.txt | AC | 5 ms | 2560 KB |
in29.txt | AC | 47 ms | 6528 KB |
in3.txt | AC | 52 ms | 6656 KB |
in30.txt | AC | 5 ms | 2560 KB |
in31.txt | AC | 52 ms | 6528 KB |
in32.txt | AC | 50 ms | 6528 KB |
in33.txt | AC | 52 ms | 6656 KB |
in34.txt | AC | 52 ms | 6528 KB |
in35.txt | AC | 51 ms | 6528 KB |
in36.txt | AC | 50 ms | 6528 KB |
in37.txt | AC | 6 ms | 2560 KB |
in38.txt | AC | 52 ms | 6656 KB |
in39.txt | AC | 53 ms | 6656 KB |
in4.txt | AC | 53 ms | 6528 KB |
in40.txt | AC | 52 ms | 6656 KB |
in41.txt | AC | 52 ms | 6528 KB |
in42.txt | AC | 54 ms | 6528 KB |
in43.txt | AC | 51 ms | 6656 KB |
in44.txt | AC | 51 ms | 6528 KB |
in45.txt | AC | 52 ms | 6528 KB |
in5.txt | AC | 52 ms | 6656 KB |
in6.txt | AC | 53 ms | 6656 KB |
in7.txt | AC | 47 ms | 6144 KB |
in8.txt | AC | 16 ms | 3456 KB |
in9.txt | AC | 52 ms | 6656 KB |
sample1.txt | AC | 5 ms | 2560 KB |
sample2.txt | AC | 5 ms | 2560 KB |
sample3.txt | AC | 5 ms | 2560 KB |