Submission #101833

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Source Code Expand

#include <cstdio>
#include <cstdlib>

int next[100002];
int s1[100002];
int s2[100002];
int minv[400002][18];
int INF=1000000007;
int N,M,eall;
int exs[400002];
int cmp(const void *ka,const void *kb) {
	int a=*(int *)ka;
	int b=*(int *)kb;
	return a-b;
}
int findpl(int x) {
	int mnv=0; int mxv=eall-1;
	while(mnv<mxv) {
		int hf=(mnv+mxv)/2;
		if(exs[hf]<x) {
			mnv=hf+1;
		} else {
			mxv=hf;
		}
	}
	return mnv;
}
int main() {
	scanf("%d%d",&N,&M);
	for(int i=0;i<N*4;i++) minv[i][0]=INF;
	for(int i=0;i<N;i++) {
		scanf("%d%d",&s1[i],&s2[i]);
		exs[i*4]=s1[i];
		exs[i*4+1]=s2[i];
		exs[i*4+2]=s1[i]+M;
		exs[i*4+3]=s2[i]+M;
	}
	qsort(exs,N*4,sizeof(int),cmp);
	for(int i=1;i<N*4;i++) {
		if(exs[i]!=exs[eall]) {
			eall++;
			exs[eall]=exs[i];
		}
	}
	eall++;
	for(int i=0;i<N;i++) {
		int s,t;
		if(s1[i]>s2[i]) {
			s=findpl(s1[i]); t=findpl(s2[i]+M);
			if(minv[s][0]>t) minv[s][0]=t;
		} else {
			s=findpl(s1[i]); t=findpl(s2[i]);
			if(minv[s][0]>t) minv[s][0]=t;
			s=findpl(s1[i]+M); t=findpl(s2[i]+M);
			if(minv[s][0]>t) minv[s][0]=t;
		}
	}
	for(int i=eall-1;i>0;i--) {
		if(minv[i-1][0]>minv[i][0]) minv[i-1][0]=minv[i][0];
	}
	for(int j=0;j<17;j++) {
		for(int i=0;i<eall;i++) {
			if(minv[i][j]<INF) {
				minv[i][j+1]=minv[minv[i][j]][j];
			} else {
				minv[i][j+1]=INF;
			}
		}
	}
	int sol=0;
	for(int i=0;i<eall;i++) {
		if(exs[i]<M) {
			int nw=i;
			int endv=findpl(exs[i]+M);
			int ksol=0;
			for(int j=17;j>=0;j--) {
				if(minv[nw][j]<=endv) {
					nw=minv[nw][j];
					ksol+=(1<<j);
				}
			}
			if(sol<ksol) sol=ksol;
		}
	}
	printf("%d\n",sol);
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result
./Main.cpp:32: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result

Judge Result