Submission #37737

#	Time	Username	Problem	Language	Result	Execution time	Memory
37737		14kg	Mountain Trek Route (IZhO12_route)	C++11	0 / 100	2000 ms	21940 KiB

route

#include <stdio.h>
#include <queue>
#include <vector>
#include <functional>
#include <algorithm>
#define next(x) (x==n?1:x+1)
#define before(x) (x==1?n:x-1)

using namespace std;
typedef pair<int, pair<int, int> > pip;
int n, m, in[1000001];
pair<int, int> go1[1000001], go2[1000001];
priority_queue<pip, vector<pip>, greater<pip> > Q;

int main() {
	int s, num = -1;
	int path, x, y, len, tot = 0, tx;
	bool check;

	scanf("%d %d", &n, &m);
	for (int i = 1; i <= n; i++) {
		scanf("%d", &in[i]);
		if (num < in[i]) num = in[i], s = i;
	//	go1[i] = { before(i),1 }, go2[i] = { next(i),1 };
	}

	path = s, len = 0, check = false;;
	for (int i = next(s); i != s; i = next(i)) {
		if (in[path] > in[i]) x = i, len = 1, check = true;
		if (in[path] == in[i]) len++;
		if (in[path] < in[i] && check) {
			Q.push({ len,{x, path} }), check = false;
			go1[path] = { x,len - 1 }, go2[x] = { path,len - 1 };
		}
		path = i;
	}
	if (in[path] < in[s] && check) {
		Q.push({ len,{x, path} });
		go1[path] = { x,len - 1 }, go2[x] = { path,len - 1 };
	}

	while ((!Q.empty()) && Q.top().first <= m) {
		len = Q.top().first, x = Q.top().second.first, y = Q.top().second.second;
		Q.pop(), m -= len ,tot++;

		in[x]++;
		if (x != y) in[y]++;

		tx = x, num = 0;
		while (in[before(tx)] == in[tx]) {
			num++, len++, tx = before(tx);
			
			if (go1[tx].second) len += go1[tx].second, tx = go1[tx].first;
			if (num > n) break;
		}
		if (in[before(tx)] == in[tx]) break;
		if (in[before(tx)] < in[tx]) continue;

		while (in[y] == in[next(y)]) {
			len++, y = next(y);

			if (go2[y].second) len += go2[y].second, y = go2[y].first;
		}

		if (in[y] < in[next(y)]) {
			Q.push({ len,{tx,y} });
			go1[y] = { tx,len - 1 }, go2[tx] = { y,len - 1 };
		}
	}
	printf("%d", tot * 2);
}

Compilation message (stderr)

route.cpp: In function 'int main()':
route.cpp:20:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &n, &m);
                        ^
route.cpp:22:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &in[i]);
                      ^
route.cpp:37:21: warning: 's' may be used uninitialized in this function [-Wmaybe-uninitialized]
  if (in[path] < in[s] && check) {
                     ^

• Subtask 1: 0 / 100