Submission #2698382

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Source Code Expand

#include "bits/stdc++.h"
using namespace std;
#define MAX 200004

char buf[MAX];
string s;

deque<int> v[MAX];

vector<pair<int, int> > star[MAX];

struct st {
	int bit[MAX];
	void add(int i, int x) {
		i++;
		while (i < MAX) {
			bit[i] += x;
			i += i&-i;
		}
	}
	int sum(int i) {
		int r = 0;
		i++;
		while (i) {
			r += bit[i];
			i -= i&-i;
		}
		return r;
	}
	st() {
		memset(bit, 0, sizeof(bit));
	}
};

st k;

int main() {
	scanf("%s", buf);
	s = buf;
	for (int i = 0; i < s.size(); i++) {
		v[s[i] - 'a'].push_back(i);
	}
	int cnt = 0;
	for (int i = 0; i < 26; i++) {
		cnt += v[i].size() % 2;
	}
	if (cnt > 1) {
		puts("-1");
		return 0;
	}
	long long int add = -1;
	for (int i = 0; i < 26; i++) {
		while (v[i].size() > 1) {
			int lef = v[i][0];
			v[i].pop_front();
			int rig = v[i].back();
			v[i].pop_back();
			star[lef].push_back(make_pair(rig, i));
		}
		if (v[i].size() == 1) {
			add = v[i][0];
		}
	}
	long long int way = 0;
	for (int i = 0; i < s.size(); i++) {
		for (int j = 0; j < star[i].size(); j++) {
			
			int en = star[i][j].first;
			if (add != -1) {
				if (i >= add || en <= add) {
					way++;
				}
			}
			way += k.sum(en) - k.sum(i);
			way += k.sum(i) * 2;
			k.add(en, 1);
		}
	}
	printf("%lld\n", way);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:38:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%s", buf);
                  ^

Judge Result