Submission #111409

#	Time	Username	Problem	Language	Result	Execution time	Memory
111409		ecasdqina	Boat (APIO16_boat)	C++14	9 / 100	6 ms	4480 KiB

boat

#include <bits/stdc++.h>
using namespace std::literals::string_literals;
using i64 = long long;
using std::cout;
using std::endl;
using std::cin;

template<typename T>
std::vector<T> make_v(size_t a){return std::vector<T>(a);}

template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts){
  return std::vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

int main() {
	int n; scanf("%d", &n); std::vector<int> a(n), b(n);
	for(int i = 0; i < n; i++) scanf("%d%d", &a[i], &b[i]);
	
	const int MOD = 1e9 + 7;
	auto dp = make_v<i64>(n + 1, n + 1); dp[0][0] = 1;
	for(int i = 0; i < n; i++) {
		assert(a[i] == b[i]);
		
		for(int j = 0; j < i + 1; j++) dp[i + 1][j] = dp[i][j];
		for(int j = 0; j < i + 1; j++) {
			if(j and a[j - 1] >= a[i]) continue;
			dp[i + 1][i + 1] += dp[i][j];
			dp[i + 1][i + 1] %= MOD;
		}
	}
	
	i64 ans = 0;
	for(int i = 1; i < dp[n].size(); i++) (ans += dp[n][i]) %= MOD;
	printf("%lld\n", ans);
	return 0;
}

Compilation message (stderr)

boat.cpp: In function 'int main()':
boat.cpp:34:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 1; i < dp[n].size(); i++) (ans += dp[n][i]) %= MOD;
                 ~~^~~~~~~~~~~~~~
boat.cpp:17:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  int n; scanf("%d", &n); std::vector<int> a(n), b(n);
         ~~~~~^~~~~~~~~~
boat.cpp:18:34: 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("%d%d", &a[i], &b[i]);
                             ~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 0 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42