NOIP模拟赛 -10.25

思路：二分检验 

　　　我的二分姿势没法检验到0

　　　0需要特判一下

#include <cstdio>
#include <cctype>
#include <algorithm>
#define min(a,b) a<b?a:b

typedef long long LL;

const int MAXN=100010;

int n;

LL sum;

struct node {
    int x,y;
    friend inline bool operator < (node x,node y) {
        return x.y<y.y;
    }
};
node e[MAXN];

inline void read(int&x) {
    int f=1;register char c=getchar();
    for(x=0;!isdigit(c);c=='-'&&(f=-1),c=getchar());
    for(;isdigit(c);x=x*10+c-48,c=getchar());
    x=x*f;
}

bool check(int x) {
    int Time=x;
    for(int i=1;i<=n;++i) {
        if(Time+e[i].x>e[i].y) return false;
        Time+=e[i].x;
    }
    return true;
}

int hh() {
    freopen("manage.in","r",stdin);
    freopen("manage.out","w",stdout);
    read(n);
    
    for(int i=1; i<=n; ++i) 
      read(e[i].x),read(e[i].y),sum+=(LL)e[i].x;
    
    std::sort(e+1,e+1+n);
    int l=0,r=e[1].y-e[1].x+1;
    while(l+1<r) {
        int mid=(l+r)>>1;
        if(check(mid)) l=mid;
        else r=mid;
    }
    
    if(!l) {
        int tot=0;
        for(int i=1; i<=n; ++i)
          if(tot+e[i].x>e[i].y) {
              printf("-1
");
              goto END;
          }
          else tot+=e[i].x;
    }
    
    printf("%d
",l);
END:
    return 0;
}

int sb=hh();
int main(int argc,char**argv) {;}

思路：51 Nod 原题 组合数取模

　　　题解：http://www.cnblogs.com/whistle13326/p/7569520.html

#include <cctype>
#include <cstdio>
#define mod 998244353

typedef long long LL;

const int MAXN=1000010;

int n,sum;

int c[MAXN];

LL fact[MAXN];

inline void read(int&x) {
    int f=1;register char c=getchar();
    for(x=0;!isdigit(c);c=='-'&&(f=-1),c=getchar());
    for(;isdigit(c);x=x*10+c-48,c=getchar());
    x=x*f;
}

inline LL quick_pow(LL a,LL k) {
    LL ret=1;
    while(k) {
        if(k&1) ret=(ret*a)%mod;
        k>>=1;
        a=(a*a)%mod;
    }
    return ret%mod;
}

inline LL C(int a,int b) {
    return fact[a]*quick_pow(fact[b]*fact[a-b]%mod,mod-2)%mod;
}

inline void Factorial() {
    fact[0]=1;
    for(int i=1;i<=MAXN;++i)
      fact[i]=(fact[i-1]*i)%mod;
}

int hh() {
    freopen("qiang.in","r",stdin);
    freopen("qiang.out","w",stdout);
    
    Factorial();
    read(n);
    for(int i=1;i<=n;++i) read(c[i]),sum+=c[i];
    
    LL ans=1;
    for(int i=n;i;--i) {
        ans=(ans*C(sum-1,c[i]-1))%mod;
        sum-=c[i];
    }
    printf("%I64d
",ans);
    return 0;
}

int sb=hh();
int main(int argc,char**argv) {;}

思路：这还是NOIP么 怎么像是树套树！！！

　　　我打的两颗线段树的暴力 只有20分

 　　 据说std是树状数组 + 分块 !!

　　　unsigned long long 只能用 llu 输出 

　　　cout 肯定超时

#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
typedef unsigned long long LL;
#define lowbit(x) ((x)&-(x))
int n;
int a[100005];
LL c[100005];
int L[100005],R[100005];
int Q;
int t[405][100005];
int belong[100005];// (i-1)/B+1
LL sum[405];
int B,NUM;
void add(int x,LL d){
    while(x<=n){
        c[x]+=d;
        x+=lowbit(x);
    }
}
LL ask(int x){
    LL ret=0;
    while(x){
        ret+=c[x];
        x-=lowbit(x);
    }
    return ret;
}
int main(){
    freopen("sum.in","r",stdin);
    freopen("sum.out","w",stdout);
    scanf("%d",&n);
    for(int i=1;i<=n;i++){
        scanf("%d",&a[i]);
    }
    for(int i=1;i<=n;i++){
        scanf("%d%d",&L[i],&R[i]);
    }
    B=sqrt(n)+1;
//  printf("#%d
",B);
    NUM=(n-1)/B+1;
    for(int i=1;i<=n;i++) belong[i]=(i-1)/B+1;
    for(int i=1;i<=n;i++) c[i]=a[i];
    for(int i=1;i<=n;i++){
        if(i+lowbit(i)<=n){
            c[i+lowbit(i)]+=c[i];
        }
    }
    for(int i=1;i<=n;i++){
        t[belong[i]][L[i]]++;
        t[belong[i]][R[i]+1]--;
    }
    for(int i=1;i<=NUM;i++){
        for(int j=1;j<=n;j++){
            t[i][j]+=t[i][j-1];
            sum[i]+=t[i][j]*1ULL*a[j];
        }
    }
    scanf("%d",&Q);
    while(Q--){
        int type,x,y;
        scanf("%d%d%d",&type,&x,&y);
        if(type==1){
            for(int i=1;i<=NUM;i++){
                sum[i]-=t[i][x]*1ULL*a[x];
                sum[i]+=t[i][x]*1ULL*y;
            }
            add(x,-a[x]);
            a[x]=y;
            add(x,a[x]);
        }else{
            int Ln,Rn;
            Ln=belong[x],Rn=belong[y];
            LL ans=0;
            if(Ln==Rn){
                for(int i=x;i<=y;i++){
                    ans+=ask(R[i])-ask(L[i]-1);
                }
            }else{
                for(int i=Ln+1;i<Rn;i++) ans+=sum[i];
                int lim;
                lim=Ln*B;
                lim=min(lim,y);
                for(int i=x;i<=lim;i++){
                    ans+=ask(R[i])-ask(L[i]-1);
                }
                lim=(Rn-1)*B+1;
                lim=max(lim,x);
                for(int i=lim;i<=y;i++){
                    ans+=ask(R[i])-ask(L[i]-1);
                }
            }
            printf("%llu
",ans);
        }
    }
    fclose(stdout);
    return 0;
}