hdu 4638 Group 莫队算法

题目链接

很裸的莫队， 就不多说了...

 #include<bits/stdc++.h>
 using namespace std;
 #define pb(x) push_back(x)
 #define ll long long
 #define mk(x, y) make_pair(x, y)
 #define lson l, m, rt<<1
 #define mem(a) memset(a, 0, sizeof(a))
 #define rson m+1, r, rt<<1|1
 #define mem1(a) memset(a, -1, sizeof(a))
 #define mem2(a) memset(a, 0x3f, sizeof(a))
 #define rep(i, a, n) for(int i = a; i<n; i++)
 #define ull unsigned long long
 typedef pair<int, int> pll;
 const double PI = acos(-1.0);
 const double eps = 1e-;
 const int mod = 1e9+;
 const int inf = ;
 const int maxn = 1e5+;
 int vis[maxn];
 int a[maxn], ans[maxn];

 struct node {
     int l, r, block, id;
     bool operator < (node x) const
     {
         if(block == x.block)
             return r < x.r;
         return block < x.block;
     }
 } q[maxn];
 int main() {
     int t, n, m;
     cin>>t;
     while (t--) {
         scanf("%d%d", &n, &m);
         int BLOCK = sqrt(n*1.0);
         for(int i=; i<=n; i++)
             scanf("%d", &a[i]);
         for(int i=; i<m; i++) {
             scanf("%d%d", &q[i].l, &q[i].r);
             q[i].block = q[i].l/BLOCK;
             q[i].id = i;
         }
         sort(q, q+m);
         mem(vis);
         int tmp = ;
         int x = q[].l, y = q[].r;
         for(int i=x; i<=y; i++) {
             vis[a[i]] = ;
             if (vis[a[i]-] && vis[a[i]+])
                 tmp--;
             else if (!vis[a[i]-] && !vis[a[i]+])
                 tmp++;
         }
         ans[q[].id] = tmp;
         int L = x, R = y;
         for(int i=; i<m; i++) {
             x = q[i].l, y = q[i].r;
             for (int i=x; i<L; i++) {
                 vis[a[i]] = ;
                 if (vis[a[i]-] && vis[a[i]+])
                     tmp--;
                 else if (!vis[a[i]-] && !vis[a[i]+])
                     tmp++;
             }
             for (int i=R+; i<=y; i++) {
                 vis[a[i]] = ;
                 if (vis[a[i]-] && vis[a[i]+])
                     tmp--;
                 else if (!vis[a[i]-] && !vis[a[i]+])
                     tmp++;
             }
             for (int i=L; i<x; i++) {
                 vis[a[i]] = ;
                 if (vis[a[i]-] && vis[a[i]+])
                     tmp++;
                 else if (!vis[a[i]-] && !vis[a[i]+])
                     tmp--;
             }
             for (int i=y+; i<=R; i++) {
                 vis[a[i]] = ;
                 if (vis[a[i]-] && vis[a[i]+])
                     tmp++;
                 else if (!vis[a[i]-] && !vis[a[i]+])
                     tmp--;
             }
             ans[q[i].id] = tmp;
             L = x, R = y;
         }
         for(int i=; i<m; i++)
             printf("%d\n", ans[i]);
     }
     return ;
 }