Submission #1518751

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Source Code Expand

#include <cstdio>
#include <vector>
#include <algorithm>
#pragma warning(disable : 4996)
using namespace std;
int N, a, b, d[100009]; vector<int> g[100009];
int solve(int pos, int pre) {
	int ret = 0, r1 = 0, r2 = 0;
	for (int i : g[pos]) {
		if (i != pre) {
			ret = max(ret, solve(i, pos));
			if (r1 < d[i]) r2 = r1, r1 = d[i];
			else if (r2 < d[i]) r2 = d[i];
		}
	}
	d[pos] = r1 + (g[pos].size() == 2 ? 1 : 0);
	return max(ret, d[pos] + r2);
}
int main() {
	scanf("%d", &N);
	for (int i = 1; i < N; i++) {
		scanf("%d %d", &a, &b); a--, b--;
		g[a].push_back(b);
		g[b].push_back(a);
	}
	int ret = 0;
	for (int i = 0; i < N; i++) ret += (g[i].size() == 1 ? 1 : 0);
	printf("%d\n", ret + solve(0, -1));
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:20:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
                 ^
./Main.cpp:22:25: 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