POJ 3067 树状数组求逆序数

来源：互联网发布：丰田世纪知乎编辑：程序博客网时间：2024/06/05 16:56

题意：日本东海岸有n个城市，西海岸有m个城市，现在要修建k条高铁连接东海岸的城市u和西海岸的城市v。问这k条高铁总共有多少个交点。

#include <stdio.h>  #include <iostream>  #include <algorithm>  #include <string.h>  #include <math.h>  #define M 1005  #define LL long long  using namespace std;    int n,m,k;  int c[M];  struct node  {      int x,y;      bool operator < ( const node &h ) const      {          return x<h.x || (x==h.x && y<h.y);      }  };  struct node p[M*M];    int Lowbit(int x)  {      return x&(-x);  }    void Update(int x,int d)  {      while(x<=M)      {          c[x]+=d;          x+=Lowbit(x);      }  }    int Sum(int x)  {      int sum=0;      while(x>0)      {          sum+=c[x];          x-=Lowbit(x);      }      return sum;  }    int main()  {      int t;      scanf("%d",&t);      for(int count=1;count<=t;count++)      {          memset(c,0,sizeof(c));          scanf("%d%d%d",&n,&m,&k);          for(int i=1;i<=k;i++)          {              scanf("%d%d",&p[i].x,&p[i].y);          }          sort(p+1,p+1+k);          LL ans=0;          for(int i=1;i<=k;i++)          {              Update(p[i].y,1);              ans+=(i-Sum(p[i].y));          }          printf("Test case %d: %lld\n",count,ans);      }      return 0;  }

#include <cmath>#include <vector>#include <string>#include <cstdio>#include <cstring>#include <algorithm>#include <functional>using namespace std;typedef __int64 int64;typedef unsigned int uint;const double EPS = 1e-8;const double PI = acos(-1.);const int INF = 0x7f7f7f7f;const int INF32 = ~0U >> 1;const int64 INF64 = ~0ULL >> 1;const int MOD = int(1e9) + 7;/* Macros */#define TR int __T;scanf("%d",&__T);while(__T--)#define NR while(~scanf("%d",&n))#define MR while(~scanf("%d%d",&n,&m))#define NO while(~scanf("%d",&n),n)#define MO while(~scanf("%d%d",&n,&m),n||m)#define SQR(x) ((x)*(x))#define ALL(x) (x).begin(),(x).end()#define lson l,mid,id<<1#define rson mid+1,r,id<<1|1#define mm (l+r)>>1const int N = 1100;int n, m, k, cas = 1;struct Link {    int l, r;    bool operator <(const Link& next) const {        if (l == next.l) {            return r < next.r;        }        return l < next.l;    }} link[1000005];void get_data() {    scanf("%d%d%d", &n, &m, &k);    for (int i = 0; i < k; i++) {        scanf("%d%d", &link[i].l, &link[i].r);    }    sort(link, link + k);}int64 in[N];int lowbit(int t) {    return t & (-t);}int64 sum(int end) {//与上面的区别    int64 sum = 0;    while (end <= 1001) {        sum += in[end];        end += lowbit(end);    }    return sum;}void add(int pos) {//区别    while (pos > 0) {        in[pos]++;        pos -= lowbit(pos);    }}void run() {    int64 tot = 0;    memset(in, 0, sizeof(in));    for (int i = 0; i < k; i++) {        int r = link[i].r;        tot += sum(r + 1);//区别        add(r);    }    printf("Test case %d: %I64d\n", cas++, tot);}int main() {    TR {        get_data();        run();    }    return 0;}

0 0