Submission #46523

#	Time	Username	Problem	Language	Result	Execution time	Memory
46523		ikura355	Cultivation (JOI17_cultivation)	C++14	5 / 100	505 ms	3708 KiB

cultivation

#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 recx[maxn*2], recy[maxn*2];
map<int,int> mpx, mpy;

int cnt[maxn*2][maxn*2];

vector<int> have[100];

void check(int up, int down, int sleft, int sright, int sgap, int sgaprow) {
			for(int row=1;row<=R;row++) have[row].clear();
			for(int x=1;x<=n;x++) {
				for(int i=max(1,p[x].X-up);i<=min(R,p[x].X+down);i++) {
					have[i].push_back(p[x].Y);
				}
			}
			for(int row=1;row<=R;row++) sort(have[row].begin(), have[row].end());
			int left = 0, right = 0, gap = 0;
			int gaprow = 0, con = 0;
            for(int row=1;row<=R;row++) {
                if(have[row].size()==0) {
                    con++;
                    gaprow = max(gaprow, con);
                }
                else {
                    con = 0;
                    left = max(left, *have[row].begin()-1);
                    right = max(right, C-*have[row].rbegin());
                }
            }
            for(int row=1;row<=R;row++) {
            	for(int i=1;i<have[row].size();i++) gap = max(gap, have[row][i]-have[row][i-1]-1-left-right);
            }
	assert(sleft==left);
	assert(sright==right);
	assert(sgap==gap);
	assert(sgaprow==gaprow);
}

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;
		recy[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(); szx = 0;
			for(int i=1;i<=n;i++) mpx[max(1,p[i].X-up)], mpx[min(R,p[i].X+down)];
			for(auto &t : mpx) {
                t.second = ++szx;
                recx[szx] = t.first;
			}

			//place
			memset(cnt,0,sizeof(cnt));
			for(int row=1;row<=szx;row++) {
				for(int i=1;i<=n;i++) {
					if(p[i].X-up <= recx[row] && recx[row] <= p[i].X+down) cnt[row][mpy[p[i].Y]] = 1;
				}
			}

			//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, recy[y] - 1);
						break;
					}
				}
				for(int y=szy;y>=1;y--) {
					if(cnt[x][y]) {
						right = max(right, C - recy[y]);
						break;
					}
				}
			}

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

			ans = min(ans, up + down + left + right + gap + gaprow);
			check(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 'void check(int, int, int, int, int, int)':
cultivation.cpp:42:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
              for(int i=1;i<have[row].size();i++) gap = max(gap, have[row][i]-have[row][i-1]-1-left-right);
                          ~^~~~~~~~~~~~~~~~~
cultivation.cpp: In function 'int main()':
cultivation.cpp:51:7: 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:52:29: 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