线段树(单点更新)/树状数组 HDOJ 1166 敌兵布阵

题目传送门

 /*
     线段树基本功能：区间值的和，修改某个值
 */
 #include <cstdio>
 #include <cstring>
 #define lson l, m, rt << 1
 #define rson m+1, r, rt << 1|1

 const int MAX_N =  + ;
 int sum[MAX_N<<];

 void pushup(int rt)            //杭电大牛：notOnlySuccess 版本
 {
     sum[rt] = sum[rt<<] + sum[rt<<|];
 }

 void build(int l, int r, int rt)
 {
     if (l == r)
     {
         scanf ("%d", &sum[rt]);
         return ;
     }
     int m = (l + r) >> ;
     build (lson);
     build (rson);
     pushup (rt);
 }

 void update(int p, int add, int l, int r, int rt)
 {
     if (l == r)
     {
         sum[rt] += add;
         return ;
     }
     int m = (l + r) >> ;
     if (p <= m)    update (p, add, lson);
     else    update  (p, add, rson);
     pushup (rt);
 }

 int query(int ql, int qr, int l, int r, int rt)
 {
     if (ql <= l && r <= qr)
     {
         return sum[rt];
     }
     int m = (l + r) >> ;
     int ans = ;
     if (ql <= m)    ans += query (ql, qr, lson);
     if (qr > m)        ans += query (ql, qr, rson);

     return ans;
 }

 int main(void)            //HDOJ 1166 敌兵布阵
 {
     //freopen ("inA.txt", "r", stdin);
     int t, n, cas, ans;
     int b, c;
     char s[];

     while (~scanf ("%d", &t))
     {
         cas = ;
         while (t--)
         {
             scanf ("%d", &n);
             build (, n, );
             printf ("Case %d:\n", ++cas);
             while (~scanf ("%s", &s))
             {
                 if (strcmp (s, "End") == )    break;
                 scanf ("%d%d", &b, &c);
                 if (strcmp (s, "Query") == )
                 {
                     ans = query (b, c, , n, );
                     printf ("%d\n", ans);
                 }
                 else if (strcmp (s, "Add") == )
                 {
                     update (b, c, , n, );
                 }
                 else if (strcmp (s, "Sub") == )
                 {
                     update (b, -c, , n, );
                 }
             }
         }
     }

     return ;
 }

 /*
     树状数组
 */
 #include <cstdio>
 #include <cstring>

 const int MAX_N =  + ;
 int a[MAX_N];
 int n, num;

 int lowbit(int t)        //求 2^k
 {
     //return t & (t ^ (t - 1));
     return t & (-t);
 }

 void plus(int num, int x)        //第i个增加num个人
 {
     while (x <= n)
     {
         a[x] += num;
         x += lowbit (x);
     }
 }

 int sum(int x)            //求前x项的和
 {
     int sum = ;
     while (x > )
     {
         sum += a[x];
         x -= lowbit(x);
     }
     return sum;
 }

 int main(void)
 {
     //freopen ("inA.txt", "r", stdin);

     int t;
     char op[];

     scanf ("%d", &t);
     int k = t;

     while (k--)
     {
         memset (a, , sizeof (a));
         scanf ("%d", &n);
         for (int i=; i<=n; ++i)
         {
             scanf ("%d", &num);
             plus (num, i);
         }
         int r = ;
         while (scanf ("%s", &op), op[] != 'E')
         {
             int a, b;
             scanf ("%d%d", &a, &b);
             switch (op[])
             {
                 case 'A':
                     plus (b, a);
                     break;
                 case 'S':
                     plus (-b, a);
                     break;
                 case 'Q':
                     if (r)
                         printf ("Case %d:\n", t - k);
                     r = ;
                     printf ("%d\n", sum (b) - sum (a-));
                     break;
             }
         }
     }

     return ;
 }

树状数组