HDU 5360 Hiking (segment tree)

Test instructions

n the condition that an individual accepts an invitation is the number of people who have accepted the invitation in L[i], R[i]
Asking how to set the order of invitations can make the number of people accepting invitations the most

Analytical:

First, the interval is sorted from small to large on the right edge, if the right boundary is the same, then the left border is sorted from small to large. Because the lower the right border, the higher the priority, the left edge is the same.
If the priority queue is used, it is calculated that choosing which interval is optimal for the current person.
Because I do not have two conditions priority queue, so can only change a way to write.
So I think of the line tree, reverse thinking, using line segment tree to maintain this interval to choose which person is the best.
After selecting this person, place the person in infinity and maintain the line tree.
and record the current person, which range is selected.

my code

#include <cstdio>#include <cstring>#include <algorithm>#define LS o<<1#define RS O<<1|1#define Lson ls, L, M#define Rson RS, m+1, Rusing namespace STD;Const intINF =0x3f3f3f3f;Const intN =1e5+Ten;intNstructNode {intL, R, id;} Node[n];intminv[n<<2];inline voidPushup (intO) {Minv[o] = min (Minv[ls], minv[rs]);}voidBuildintOintLintR) {if(L = = R) {Minv[o] = L;return; }intM = (L + R)/2;    Build (Lson);    Build (Rson); Pushup (o);}intQueryintOintLintRintQlintQR) {if(QL <= L && R <= qr)returnMinv[o];intM = (L + R)/2, ret = INF;if(QL <= M) ret = min (ret, query (Lson, QL, QR));if(QR > M) ret = min (ret, query (Rson, QL, QR));returnRET;}voidModifyintOintLintRintPOS) {if(L = = R) {Minv[o] = INF;return; }intM = (L + R)/2;if(POS <= M) Modify (Lson, POS);ElseModify (Rson, POS); Pushup (o);}intAns[n], res[n];BOOLVis[n];BOOLCMP (Node A, Node B) {if(A.R! = B.R)returnA.R < B.R;returnA.l < B.L;}intMain () {intTscanf("%d", &t); while(t--) {scanf("%d", &n); for(inti =1; I <= N; i++) {scanf("%d", &AMP;NODE[I].L);        Node[i].id = i; } for(inti =1; I <= N; i++)scanf("%d", &AMP;NODE[I].R); Sort (node+1, node+n+1, CMP);memset(ANS,-1,sizeof(ans));memset(Vis,false,sizeof(VIS)); Build1,0, n); for(inti =1; I <= N; i++) {intret = Query (1,0, N, NODE[I].L, NODE[I].R);if(ret! = INF)                {Ans[ret] = node[i].id; Modify1,0, N, ret); }        }inttot =0; for(inti =0; I < n; i++) {if(Ans[i]! =-1) {res[tot++] = ans[i]; Vis[ans[i]] =true; }Else  Break; }printf("%d\n", tot); for(inti =1; I <= N; i++) {if(!vis[i]) res[tot++] = i; } for(inti =0; i < tot; i++) {printf("%d", Res[i]);if(i = = tot-1)puts("");Else Putchar("'); }    }return 0;}

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HDU 5360 Hiking (segment tree)