Submission #46515

#	Time	Username	Problem	Language	Result	Execution time	Memory
46515		ikura355	Cultivation (JOI17_cultivation)	C++14	5 / 100	3 ms	748 KiB

cultivation

//#3
#include<bits/stdc++.h>
using namespace std;
#define pii pair<int,int>
#define X first
#define Y second
const int maxn = 300 + 5;
const int inf = 1e9;
int n,R,C;
pii p[maxn];
vector<int> forup, fordown;

int szx, szy;
int rec[maxn];
map<int,int> mpx, mpy;

int cnt[maxn*2][maxn];

int main() {
	scanf("%d%d%d",&R,&C,&n);
	for(int i=1;i<=n;i++) scanf("%d%d",&p[i].X,&p[i].Y);

	//prep
	sort(&p[1],&p[n+1]);
	for(int i=1;i<=n;i++) mpy[p[i].Y];
	for(auto &t : mpy) {
		t.second = ++szy;
		rec[szy] = t.first;
	}
	for(int i=1;i<=n;i++) {
		forup.push_back(p[i].X-1);
		fordown.push_back(R-p[i].X);
	}

	//solve
	int ans = inf;
	for(auto up : forup) {
		for(auto down : fordown) {
			//gap row
			int gaprow = 0;
			for(int i=2;i<=n;i++) gaprow = max(gaprow, p[i].X-p[i-1].X-1-up-down);

			//cpidx for x
			mpx.clear();
			for(int i=1;i<=n;i++) mpx[max(1,p[i].X-up)], mpx[min(R,p[i].X+down)];
			int szx = 0;
			for(auto &t : mpx) t.second = ++szx;

			//place
			for(int x=1;x<=szx;x++) for(int y=1;y<=szy;y++) cnt[x][y] = 0;
			for(int i=1;i<=n;i++) cnt[mpx[max(1,p[i].X-up)]][mpy[p[i].Y]]++, cnt[mpx[min(R,p[i].X+down)]+1][mpy[p[i].Y]]--;
			for(int x=1;x<=szx;x++) for(int y=1;y<=szy;y++) cnt[x][y] += cnt[x-1][y];

			//show
//			printf("up = %d down = %d\n",up,down);
//			for(int x=1;x<=szx;x++) {
//                for(int y=1;y<=szy;y++) printf("%d ",cnt[x][y]);
//                printf("\n");
//			}
//			printf("-------------------------\n");

			//left and right
			int left = 0, right = 0;
			for(int x=1;x<=szx;x++) {
				for(int y=1;y<=szy;y++) {
					if(cnt[x][y]) {
						left = max(left, rec[y] - 1);
						break;
					}
				}
				for(int y=szy;y>=1;y--) {
					if(cnt[x][y]) {
						right = max(right, C - rec[y]);
						break;
					}
				}
			}

			//gap
			int gap = 0;
			for(int x=1;x<=szx;x++) {
				int last = -1;
				for(int y=1;y<=szy;y++) {
					if(last!=-1) {
						gap = max(gap, rec[y] - rec[last] - 1 - left - right);
					}
					last = y;
				}
			}

			ans = min(ans, up + down + left + right + gap + gaprow);

//			printf("up = %d down = %d (%d) : use %d %d %d\n",up,down,gaprow,left,right,gap);
		}
	}
	printf("%d",ans);
}

Compilation message (stderr)

cultivation.cpp: In function 'int main()':
cultivation.cpp:20:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d",&R,&C,&n);
  ~~~~~^~~~~~~~~~~~~~~~~~~
cultivation.cpp:21:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  for(int i=1;i<=n;i++) scanf("%d%d",&p[i].X,&p[i].Y);
                        ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 30
• Subtask 5: 0 / 20
• Subtask 6: 0 / 20