delete pics to save space

7.2374.cpp

@@ -0,0 +1,60 @@
+#include<cstdio>
+#include<cstring>
+#include<algorithm>
+using namespace std;
+#define Lc (o<<1)
+#define Rc (o<<1|1)
+const int maxn=50005;
+const int maxidx=200005;
+int n,s,p[maxn][2],d[maxn][2],f[maxn][2];
+int a[maxidx<<2],pl,pr,v;
+inline void pushdown(int o) { a[Lc]=max(a[Lc],a[o]); a[Rc]=max(a[Rc],a[o]); }
+void update(int o,int L,int R)
+{
+	if(pl<=L&&R<=pr) { a[o]=max(a[o],v); return; }
+	pushdown(o);
+	int M=(L+R)>>1;
+	if(pl<=M)
+		update(Lc,L,M);
+	if(pr>M)
+		update(Rc,M+1,R);
+}
+int query(int o,int L,int R,int p,int v)
+{
+	if(L==R) return max(v,a[o]);
+	int M=(L+R)>>1;
+	if(p<=M) return query(Lc,L,M,p,max(v,a[o]));
+	else return query(Rc,M+1,R,p,max(v,a[o]));
+}
+inline void ckmin(int &a,int b) { a=min(a,b); }
+int main()
+{
+	#ifdef local
+	freopen("pro.in","r",stdin);
+	#endif
+	memset(f,0x3f,sizeof(f));
+	scanf("%d%d",&n,&s);
+	for(int i=1;i<=n;i++)
+	{
+		scanf("%d%d",&p[i][0],&p[i][1]);
+		p[i][0]+=100001; p[i][1]+=100001;
+		d[i][0]=query(1,1,maxidx-5,p[i][0],0);
+		d[i][1]=query(1,1,maxidx-5,p[i][1],0);
+		// printf("i=%d %d %d\n",i,d[i][0],d[i][1]);
+		v=i; pl=p[i][0]; pr=p[i][1];
+		update(1,1,maxidx-5);
+	}
+	s+=100001;
+	f[n][0]=abs(s-p[n][0]); f[n][1]=abs(s-p[n][1]);
+	p[0][0]=p[0][1]=100001;
+	for(int i=n;i>=1;i--)
+		for(int j=0;j<=1;j++)
+		{
+			// printf("f[%d][%d]=%d\n",i,j,f[i][j]);
+			int v=min(f[i][j],f[i][j^1]+abs(p[i][0]-p[i][1])),to=d[i][j];
+			f[to][0]=min(f[to][0],v+abs(p[i][j]-p[to][0]));
+			f[to][1]=min(f[to][1],v+abs(p[i][j]-p[to][1]));
+		}
+	printf("%d\n",f[0][0]);
+	return 0;
+}