BZOJ1067(SCOI2007)[降雨量]--RMQ

来源：互联网发布：中文版热力学模拟软件编辑：程序博客网时间：2024/06/08 16:20

【链接】
bzoj1067

【解题报告】

对于每次询问Y和X，满足aY<aZ(Y+1<=Z<=X−1)<aX,可以直接用RMQ知道aZ 的大小，这题再注意一下一些细节就可以过了。

#include<cstdio>#include<cmath>#include<algorithm>using namespace std;const int maxn=50005,maxv=16;int n,m,a[maxn],f[maxn][maxv];inline char nc(){    static char buf[100000],*l,*r;    if (l==r) r=(l=buf)+fread(buf,1,100000,stdin);    if (l==r) return EOF; return *l++;}inline int Read(){    int res=0,f=1; char ch=nc(),cc=ch;    while (ch<'0'||ch>'9') cc=ch,ch=nc();    if (cc=='-') f=-1;    while (ch>='0'&&ch<='9') res=res*10+ch-48,ch=nc();    return res*f;}void RMQ(){    for (int k=log2(n),j=1; j<=k; j++)     for (int i=1; i<=n-(1<<j)+1; i++)      f[i][j]=max(f[i][j-1],f[i+(1<<j-1)][j-1]);}int Find(int x){    int L=1,R=n;    while (L<=R)    {        int mid=(R-L>>1)+L;        if (a[mid]==x) return mid;        if (a[mid]<x) L=mid+1; else R=mid-1;    }    return 0;}int Find2(int x){    int L=1,R=n;    while (L<=R)    {        int mid=(R-L>>1)+L;        if (a[mid]<x) L=mid+1; else R=mid-1;    }    return L;}int main(){    freopen("1067.in","r",stdin);    freopen("1067.out","w",stdout);    n=Read();    for (int i=1; i<=n; i++) a[i]=Read(),f[i][0]=Read();    RMQ(); m=Read();    for (int i=1; i<=m; i++)    {        int x=Read(),y=Read(),L=Find(x),R=Find(y);        if (!L&&!R) {printf("maybe\n"); continue;}        if (!L&&R)         {            L=Find2(x)-1; L++; R--; int k=log2(R-L+1),p=0;            if (L<=R) p=max(f[L][k],f[R-(1<<k)+1][k]);            if (p>=f[R+1][0]) printf("false\n"); else printf("maybe\n");            continue;         }        if (L&&!R)         {            R=Find2(y); L++; R--; int k=log2(R-L+1),p=0;            if (L<=R) p=max(f[L][k],f[R-(1<<k)+1][k]);            if (f[L-1][0]>p) printf("maybe\n"); else printf("false\n");            continue;         }        if (f[L][0]<=f[R][0]) {printf("false\n"); continue;}        L++; R--; int k=log2(R-L+1),p=0;        if (L<=R) p=max(f[L][k],f[R-(1<<k)+1][k]);        if (p>=f[R+1][0]) printf("false\n");         else if (R-L+2<y-x) printf("maybe\n");          else printf("true\n");    }    return 0;}

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