Submission #3895806

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Source Code Expand

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <algorithm>
#include <cmath>
#include <vector>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <queue>
#include <ctime>
#include <cassert>
#include <complex>
#include <string>
#include <cstring>
#include <chrono>
#include <random>
#include <queue>
#include <bitset>
using namespace std;

#ifdef LOCAL
	#define eprintf(...) fprintf(stderr, __VA_ARGS__)
#else
	#define eprintf(...) 42
#endif

typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, int> pli;
typedef pair<ll, ll> pll;
typedef long double ld;
#define mp make_pair
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int MOD = (int)1e9 + 7;
int add(int x, int y) {
	x += y;
	if (x >= MOD) return x - MOD;
	return x;
}
int sub(int x, int y) {
	x -= y;
	if (x < 0) return x + MOD;
	return x;
}
int mult(int x, int y) {
	return ((ll)x * y) % MOD;
}
int div2(int x) {
	if (x & 1) x += MOD;
	return x / 2;
}

const int N = 3030;
int a[N];
int xs[N];
int n, m, k;
int b[N][2];
int c[N], d[N];
int ans;

int main()
{
//	freopen("input.txt", "r", stdin);
//	freopen("output.txt", "w", stdout);

	scanf("%d%d", &n, &m);
	for (int i = 0; i < n; i++) {
		scanf("%d", &a[i]);
		xs[i] = a[i];
	}
	sort(xs, xs + n);
	k = unique(xs, xs + n) - xs;
	for (int i = 0; i < n; i++)
		a[i] = lower_bound(xs, xs + k, a[i]) - xs;
	for (int i = 0; i < m; i++)
		for (int j = 0; j < 2; j++) {
			scanf("%d", &b[i][j]);
			b[i][j]--;
		}
	for (int it = k - 1; it >= 0; it--) {
		for (int i = 0; i < n; i++)
			c[i] = (int)(a[i] == it);
		for (int i = 0; i < m; i++) {
			int x = div2(add(c[b[i][0]], c[b[i][1]]));
			c[b[i][0]] = c[b[i][1]] = x;
		}
		int sum = 0;
		for (int i = 0; i < n; i++) {
			ans = add(ans, mult(sum, c[i]));
			ans = add(ans, div2(mult(c[i], d[i])));
			sum = add(sum, d[i]);
			d[i] = add(d[i], c[i]);
		}
	}
	for (int i = 0; i < m; i++) {
		ans = add(ans, ans);
	}
	printf("%d\n", ans);

	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:69:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d", &n, &m);
                       ^
./Main.cpp:71:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &a[i]);
                     ^
./Main.cpp:80:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
    scanf("%d", &b[i][j]);
                         ^

Judge Result