Submission #845794

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define REP(i, a, b) for (int i = (a), i##_end_ = (b); i < i##_end_; ++i)
#define debug(...) fprintf(stderr, __VA_ARGS__)
#define mp make_pair
#define x first
#define y second
#define pb push_back
#define SZ(x) (int((x).size()))
#define ALL(x) (x).begin(), (x).end()

template<typename T> inline bool chkmin(T &a, const T &b) { return a > b ? a = b, 1 : 0; }
template<typename T> inline bool chkmax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }

typedef long long LL;

const int oo = 0x3f3f3f3f;

const int maxn = 100000;

int n;
int a[maxn + 5];

inline void deal()
{
	vector<int> u, v;
	REP(i, 0, n)
	{
		if (i & 1) u.pb(a[i]);
		else v.pb(a[i]);
	}
	sort(ALL(u), greater<int>());
	sort(ALL(v), greater<int>());
	REP(i, 0, n)
	{
		if (i & 1) a[i] = u.back(), u.pop_back();
		else a[i] = v.back(), v.pop_back();
	}
}

int main()
{
#ifdef matthew99
	freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
	scanf("%d", &n);
	vector<int> v;
	REP(i, 0, n)
	{
		scanf("%d", a + i);
		v.pb(a[i]);
	}
	sort(ALL(v));
	REP(i, 0, n) a[i] = lower_bound(ALL(v), a[i]) - v.begin() + 1;
	deal();
	static int sum[maxn + 5];
	memset(sum, 0, sizeof sum);
	LL ret = 0;
	REP(i, 0, n)
	{
		for (int j = a[i]; j <= n; j += j & -j) ret += sum[j];
		for (int j = a[i]; j > 0; j -= j & -j) ++sum[j];
	}
	cout << ret << endl;
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:49:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
                 ^
./Main.cpp:53:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", a + i);
                     ^

Judge Result