Hdu 4638 Group (offline line segment tree)

After so long, I finally made an offline line segment tree .... I personally think that if the inquiry will affect each other, I will use the so-called "offline...

This question is considered to add numbers one by one from left to right. If a [I]-1 or a [I] + 1 is added, the total number of segments remains unchanged. If both ends are merged, the number of segments is reduced by one. If none are added, adding a [I] is equivalent to adding a new segment.

Process all requests from the right endpoint from small to large (a large range, the added elements will affect the small range); process the Edge Addition.

 

include<algorithm>  #include<iostream>  #include<cstring>  #include<cstdlib>  #include<fstream>  #include<sstream>  #include<bitset>  #include<vector>  #include<string>  #include<cstdio>  #include<cmath>  #include<stack>  #include<queue>  #include<stack>  #include<map>  #include<set>  #define FF(i, a, b) for(int i=a; i<b; i++)  #define FD(i, a, b) for(int i=a; i>=b; i--)  #define REP(i, n) for(int i=0; i<n; i++)  #define CLR(a, b) memset(a, b, sizeof(a))  #define debug puts("**debug**")  #define LL long long  #define PB push_back  using namespace std;  const int maxn = 100001; int a[maxn], c[maxn], pos[maxn], ans[maxn]; int n, m; struct Q {     int l, r, id;     bool operator < (const Q rhs) const     {         return r < rhs.r;     } }q[maxn];  int low(int x) {return x & (-x);} void add(int x, int v) {     while(x <= n)     {         c[x] += v;         x += low(x);     } } int getsum(int x) {     int ret = 0;     while(x > 0)     {         ret += c[x];         x -= low(x);     }     return ret; }  int main() {     int T; scanf("%d", &T);     while(T--)     {         scanf("%d%d", &n, &m);         FF(i, 1, n+1) scanf("%d", &a[i]), pos[a[i]] = i, c[i] = 0;         REP(i, m) scanf("%d%d", &q[i].l, &q[i].r), q[i].id = i;         sort(q, q+m);         int j = 1;         for(int i=0; i<m; )         {             if(q[i].r < j)             {                 ans[q[i].id] = getsum(q[i].r) - getsum(q[i].l-1);                 i++;             }             else             {                 add(j, 1);                 if(a[j] > 1 && pos[a[j]-1] < j) add(pos[a[j]-1], -1);                 if(a[j] < n && pos[a[j]+1] < j) add(pos[a[j]+1], -1);                 j++;             }         }         REP(i, m) printf("%d\n", ans[i]);     }     return 0; } #include<algorithm>#include<iostream>#include<cstring>#include<cstdlib>#include<fstream>#include<sstream>#include<bitset>#include<vector>#include<string>#include<cstdio>#include<cmath>#include<stack>#include<queue>#include<stack>#include<map>#include<set>#define FF(i, a, b) for(int i=a; i<b; i++)#define FD(i, a, b) for(int i=a; i>=b; i--)#define REP(i, n) for(int i=0; i<n; i++)#define CLR(a, b) memset(a, b, sizeof(a))#define debug puts("**debug**")#define LL long long#define PB push_backusing namespace std;const int maxn = 100001;int a[maxn], c[maxn], pos[maxn], ans[maxn];int n, m;struct Q{    int l, r, id;    bool operator < (const Q rhs) const    {        return r < rhs.r;    }}q[maxn];int low(int x) {return x & (-x);}void add(int x, int v){    while(x <= n)    {        c[x] += v;        x += low(x);    }}int getsum(int x){    int ret = 0;    while(x > 0)    {        ret += c[x];        x -= low(x);    }    return ret;}int main(){    int T; scanf("%d", &T);    while(T--)    {        scanf("%d%d", &n, &m);        FF(i, 1, n+1) scanf("%d", &a[i]), pos[a[i]] = i, c[i] = 0;        REP(i, m) scanf("%d%d", &q[i].l, &q[i].r), q[i].id = i;        sort(q, q+m);        int j = 1;        for(int i=0; i<m; )        {            if(q[i].r < j)            {                ans[q[i].id] = getsum(q[i].r) - getsum(q[i].l-1);                i++;            }            else            {                add(j, 1);                if(a[j] > 1 && pos[a[j]-1] < j) add(pos[a[j]-1], -1);                if(a[j] < n && pos[a[j]+1] < j) add(pos[a[j]+1], -1);                j++;            }        }        REP(i, m) printf("%d\n", ans[i]);    }    return 0;}