HDU-4648 Magic Pen 6 简单题

　　题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=4648

　　求遍前缀和，然后扫描标记下就可以了。。。

  1 //STATUS:C++_AC_453MS_1792KB

  2 #include <functional>

  3 #include <algorithm>

  4 #include <iostream>

  5 //#include <ext/rope>

  6 #include <fstream>

  7 #include <sstream>

  8 #include <iomanip>

  9 #include <numeric>

 10 #include <cstring>

 11 #include <cassert>

 12 #include <cstdio>

 13 #include <string>

 14 #include <vector>

 15 #include <bitset>

 16 #include <queue>

 17 #include <stack>

 18 #include <cmath>

 19 #include <ctime>

 20 #include <list>

 21 #include <set>

 22 #include <map>

 23 using namespace std;

 24 //#pragma comment(linker,"/STACK:102400000,102400000")

 25 //using namespace __gnu_cxx;

 26 //define

 27 #define pii pair<int,int>

 28 #define mem(a,b) memset(a,b,sizeof(a))

 29 #define lson l,mid,rt<<1

 30 #define rson mid+1,r,rt<<1|1

 31 #define PI acos(-1.0)

 32 //typedef

 33 typedef __int64 LL;

 34 typedef unsigned __int64 ULL;

 35 //const

 36 const int N=100010;

 37 const int INF=0x3f3f3f3f;

 38 const int MOD=10007,STA=8000010;

 39 const LL LNF=1LL<<55;

 40 const double EPS=1e-9;

 41 const double OO=1e30;

 42 const int dx[4]={-1,0,1,0};

 43 const int dy[4]={0,1,0,-1};

 44 const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};

 45 //Daily Use ...

 46 inline int sign(double x){return (x>EPS)-(x<-EPS);}

 47 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}

 48 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}

 49 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}

 50 template<class T> inline T Min(T a,T b){return a<b?a:b;}

 51 template<class T> inline T Max(T a,T b){return a>b?a:b;}

 52 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}

 53 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}

 54 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}

 55 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}

 56 //End

 57 

 58 struct Node{

 59     int s,id;

 60     bool operator < (const Node& a)const {

 61         return s!=a.s?s<a.s:id<a.id;

 62     }

 63 }st[N];

 64 int num[N],sum[N];

 65 int n,m;

 66 

 67 int binary(int l,int r,int tar)

 68 {

 69     int mid;

 70     while(l<r){

 71         mid=(l+r)>>1;

 72         if(st[mid].s<=tar)l=mid+1;

 73         else r=mid;

 74     }

 75     return l;

 76 }

 77 

 78 int main(){

 79  //   freopen("in.txt","r",stdin);

 80     int i,j,ans,w;

 81     while(~scanf("%d%d",&n,&m))

 82     {

 83         sum[0]=0;

 84         for(i=1;i<=n;i++){

 85             scanf("%d",&num[i]);

 86             sum[i]=((sum[i-1]+num[i])%m+m)%m;

 87             st[i].s=sum[i];

 88             st[i].id=i;

 89         }

 90         sort(st+1,st+n+1);

 91         ans=0;

 92         for(i=0;i<n && ans<n-i;i++){

 93             w=binary(1,n+1,sum[i]);

 94             if(st[w-1].s==sum[i] &&  st[w-1].id>i)ans=Max(ans,st[w-1].id-i);

 95         }

 96 

 97         printf("%d\n",ans);

 98     }

 99     return 0;

100 }