Hihocoder 1080 segment Tree (interval update)

Topic Link: http://hihocoder.com/problemset/problem/1080, two operation segment tree (interval update).

This problem a period of time has been stuck to me, then also the foundation is not solid do not come out, today again think of actually still relatively simple, also can only blame oneself too weak.

　This is a pit on the pit. There are two operations: set and add, so the lazy tag array requires two, but one thing to consider is the sequence of set and add on an interval--if there is simultaneous presence of an interval set and an add tag, Then it should be handled if: a case set before add, then in the normal order to be able to, and the other case add before set, then the add operation is canceled, the direct set operation is OK.

So when updating an interval of a segment tree, if it is a set operation, the tag of the add is cleaned out, and if it is an add operation, it is done normally. This ensures that the two tags appear at the same time as the set and then add, so that there will be no error.

#include <iostream>#include<cstdio>#include<vector>#include<cmath>#include<string>#include<string.h>#include<algorithm>using namespacestd;#defineLL __int64#defineEPS 1e-8#defineINF Int_max#defineLson L, M, RT << 1#defineRson m + 1, R, RT << 1 | 1Const intMOD =10000007; Const intMAXN =100000+5;Const intN =100000+5;intSUM[MAXN <<2], COL_ADD[MAXN <<2], COL_SET[MAXN <<2];voidPushup (intRT) {Sum[rt]= Sum[rt <<1] + sum[rt <<1|1];}voidBuildintLintRintRT) {    if(L = =r) {scanf ("%d", &Sum[rt]); return; }    intm = (L + r) >>1;    Build (Lson);    Build (Rson); Pushup (RT);}voidPushdown (intRtintLen) {            //in the Pushdown () function, the set operation is performed before the add operation.    if(Col_set[rt]) {col_set[rt<<1] = Col_set[rt <<1|1] =Col_set[rt]; Col_add[rt<<1] = Col_add[rt <<1|1] =0;//also clear out the add mark, then less this sentence debug for a long timeSum[rt <<1] = (Len-(Len >>1)) *Col_set[rt]; Sum[rt<<1|1] = (Len >>1) *Col_set[rt]; COL_SET[RT]=0; }    if(Col_add[rt]! =0) {Col_add[rt<<1] +=Col_add[rt]; Col_add[rt<<1|1] +=Col_add[rt]; Sum[rt<<1] + = (len-(Len >>1)) *Col_add[rt]; Sum[rt<<1|1] + = (len >>1) *Col_add[rt]; COL_ADD[RT]=0; } }voidUpdateintLintRintXintChintLintRintRT) {    if(l <= l && R >=r) {if(CH) {SUM[RT]= (R-l +1) *x; COL_SET[RT]=x; COL_ADD[RT]=0;//clear the Add tag}Else{Sum[rt]+ = (r-l +1) *x; COL_ADD[RT]+=x; }        return; } pushdown (RT, R-L +1); intm = (L + r) >>1; if(L >m) Update (L, R, x, CH, rson); Else if(R <=m) Update (L, R, x, CH, lson); Else{update (L, R, x, CH, lson);    Update (L, R, x, CH, rson); } pushup (RT);}intMain () {intN, M, A, B, C, ch; scanf ("%d%d", &n, &m); Build (1, n +1,1);  while(m--) {scanf ("%d %d%d%d", &ch, &a, &b, &c); Update (a+1, B +1, C, CH,1, n +1,1); printf ("%d\n", sum[1]); }    return 0;}

Hihocoder 1080 segment Tree (interval update)