Submission #90982

#	Time	Username	Problem	Language	Result	Execution time	Memory
90982		tincamatei	Circle selection (APIO18_circle_selection)	C++14	49 / 100	3075 ms	352544 KiB

circle_selection

#include <bits/stdc++.h>

using namespace std;

unordered_map<int, unordered_map<int, vector<int> > > grid;

const int MAX_N = 300000;
int xc[1+MAX_N], yc[1+MAX_N], rc[1+MAX_N];
int rez[1+MAX_N];
int poz[1+MAX_N];

void rescale(int n, int d) {
	grid.clear();
	for(int i = 1; i <= n; ++i)
		if(rez[i] == 0)
			grid[xc[i] / d][yc[i] / d].push_back(i);
}

bool cmp(int a, int b) {
	return rc[a] > rc[b] || (rc[a] == rc[b] && a < b);
}

double dist(int a, int b) {
	return sqrt((long long)(xc[a] - xc[b]) * (xc[a] - xc[b]) +
	            (long long)(yc[a] - yc[b]) * (yc[a] - yc[b]));
}

int main() {
#ifdef HOME
	FILE *fin = fopen("input.in", "r");
	FILE *fout = fopen("output.out", "w");
#else
	FILE *fin = stdin;
	FILE *fout = stdout;
#endif

	int n;
	int mnx, mny;

	mnx = mny = 1000000000;
	
	fscanf(fin, "%d", &n);
	for(int i = 1; i <= n; ++i) {
		fscanf(fin, "%d%d%d", &xc[i], &yc[i], &rc[i]);
		mnx = min(mnx, xc[i]);
		mny = min(mny, yc[i]);
		poz[i - 1] = i;
	}

	for(int i = 1; i <= n; ++i) {
		xc[i] -= mnx;
		yc[i] -= mny;
	}

	sort(poz, poz + n, cmp);

	int lastr = (1 << 30);
	rescale(n, lastr);

	for(int i = 0; i < n; ++i) {
		int p = poz[i];
		if(rez[p] == 0) {
			while(rc[p] * 2 <= lastr) {
				lastr = rc[p];
				rescale(n, lastr);
			}

			int x = xc[p] / lastr, y = yc[p] / lastr;

			for(int i = x - 2; i <= x + 2; ++i)
				for(int j = y - 2; j <= y + 2; ++j) {
					for(auto it: grid[i][j])
						if(rez[it] == 0 && dist(p, it) <= rc[p] + rc[it])
							rez[it] = p;
				}
		}
	}

	for(int i = 1; i <= n; ++i)
		fprintf(fout, "%d ", rez[i]);

#ifdef HOME
	fclose(fin);
	fclose(fout);
#endif
	return 0;
}

Compilation message (stderr)

circle_selection.cpp: In function 'int main()':
circle_selection.cpp:42:8: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  fscanf(fin, "%d", &n);
  ~~~~~~^~~~~~~~~~~~~~~
circle_selection.cpp:44:9: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   fscanf(fin, "%d%d%d", &xc[i], &yc[i], &rc[i]);
   ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 12 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 30 / 30
• Subtask 6: 0 / 13