UVA 11992 ——线段树（区间修改）

解题思路：

　　将矩阵每一行建立一棵线段树，进而变成一维问题求解。注意数组要开 4*N

代码如下：

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <algorithm>

 using namespace std;
 const int maxn =  + ;

 const int INF = ;
 int q, x1_, x2_, y1, y2, v_add, v_set;

 struct segment_tree {
     int sumv[4*maxn],minv[4*maxn],maxv[4*maxn];
     int addv[4*maxn], setv[4*maxn];
     void maintain(int o, int L, int R) {
         int lc = *o, rc = *o + ;
         sumv[o] = minv[o] = maxv[o] = ;
         if(setv[o] >= ) {
             sumv[o] = setv[o] * (R-L+);
             minv[o] = maxv[o] = setv[o];
         }
         else if(R > L) {
             sumv[o] = sumv[lc] + sumv[rc];
             minv[o] = min(minv[lc], minv[rc]);
             maxv[o] = max(maxv[lc], maxv[rc]);
         }
         minv[o] += addv[o]; maxv[o] += addv[o]; sumv[o] += addv[o] * (R-L+);
     }
     void pushdown(int o) {
         int lc = *o, rc = *o+;
         if(setv[o] >= ) {
             setv[lc] = setv[rc] = setv[o];
             addv[lc] = addv[rc] = ;
             setv[o] = -;
         }
         if(addv[o] > ) {
             addv[lc] += addv[o];
             addv[rc] += addv[o];
             addv[o] = ;
         }
     }
     void update_add(int o, int L, int R) {
         int lc = *o, rc = o*+;
         if(y1 <= L && y2 >= R) {
             addv[o] += v_add;
         }
         else {
             pushdown(o);
             int M = L + (R-L)/;
             if(y1 <= M) update_add(lc, L, M); else maintain(lc, L, M);
             if(y2 > M) update_add(rc, M+, R);else maintain(rc, M+, R);
         }
         maintain(o, L, R);
     }
     void update_set(int o, int L, int R) {
         int lc = *o, rc = o*+;
         if(y1 <= L && y2 >= R) {
             setv[o] = v_set;
             addv[o] = ;
         }
         else {
             pushdown(o);
             int M = L + (R-L)/;
             if(y1 <= M) update_set(lc, L, M); else maintain(lc, L, M);
             if(y2 > M) update_set(rc, M+, R); else maintain(rc, M+, R);
         }
         maintain(o, L, R);
     }

     void query(int o, int L, int R, int add, int& _min, int& _max, int& _sum) {
         if(setv[o] >= ) {
             _sum += (add+setv[o]+addv[o]) * (min(R, y2)-max(L, y1)+);
             _min = min(_min, setv[o]+addv[o]+add);
             _max = max(_max, setv[o]+addv[o]+add);
         }
         else if(y1 <= L && y2 >= R) {
             _sum += sumv[o] + add * (R-L+);
             _min = min(_min, minv[o]+add);
             _max = max(_max, maxv[o]+add);
         }
         else {
             int M = L + (R-L)/;
             if(y1 <= M) query(o*, L, M, add+addv[o], _min, _max, _sum);
             if(y2 > M) query(o*+, M+, R, add+addv[o], _min, _max, _sum);
         }
     }

     void init() {
         memset(setv, -, sizeof setv);
         memset(addv, , sizeof addv);
         memset(sumv, , sizeof sumv);
         memset(minv, , sizeof minv);
         memset(maxv, , sizeof maxv);
     }
 };
 int r, c, m;
 const int maxr =  + ;

 segment_tree tree[maxr];

 int main(int argc, const char * argv[]) {

     while(scanf("%d%d%d", &r, &c, &m) == ){

         for(int i = ; i < maxr; i++) tree[i].init();
         for(int i = ; i < m; i++) {

             scanf("%d%d%d%d%d", &q, &x1_, &y1, &x2_, &y2);
             if(q == ){
                 scanf("%d", &v_add);
                 for(int x = x1_; x <= x2_; x++) {
                     tree[x].update_add(, , c);
                 }
             }
             if(q == ) {
                 scanf("%d", &v_set);
                 for(int x = x1_; x <= x2_; x++) {
                     tree[x].update_set(, , c);
                 }
             }
             if(q == ){
                 int gmin = INF, gmax = -INF, gsum = ;
                 for(int x = x1_; x <= x2_; x++) {
                     int _min = INF, _max = -INF, _sum = ;
                     tree[x].query(, , c, ,_min, _max, _sum);
                     gsum += _sum;
                     gmin = min(gmin, _min);
                     gmax = max(gmax, _max);
                 }
                 printf("%d %d %d\n",  gsum, gmin, gmax);
             }
         }
     }
     return ;
 }