mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
110 lines
2.4 KiB
C++
110 lines
2.4 KiB
C++
#include <iostream>
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#include <cstdlib>
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#include <cstdio>
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#include <cstring>
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#define LL long long
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#define INF 0x3f3f3f3f
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#define msz 405000
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#define Max 50000000000000
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using namespace std;
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typedef struct LinkTree
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{
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LL sum[2][2];
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}LinkTree;
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LinkTree tr[405005];
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int n,m;
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LinkTree Joint(LinkTree a,LinkTree b)
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{
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int i,j;
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LL t;
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LinkTree tmp;
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for(i = 0; i < 2; ++i)
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{
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for(j = 0; j < 2; ++j)
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{
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tmp.sum[i][j] = max(a.sum[i][j],b.sum[i][j]);
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t = max(a.sum[i][0]+b.sum[1][j],a.sum[i][1]+b.sum[0][j]);
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tmp.sum[i][j] = max(tmp.sum[i][j],t);
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}
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}
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return tmp;
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}
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void SetTree(int site,int l,int r)
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{
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int i,j,x;
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if(l == r)
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{
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scanf("%d",&x);
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for(i = 0; i < 2; ++i)
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for(j = 0; j < 2; ++j)
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tr[site].sum[i][j] = -Max;
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tr[site].sum[l&1][r&1] = x;
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return;
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}
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int m = (l+r)>>1;
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SetTree(site<<1,l,m);
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SetTree(site<<1|1,m+1,r);
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tr[site] = Joint(tr[site<<1],tr[site<<1|1]);
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}
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void Change(int site,int l,int r,int k,int data)
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{
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if(l == k && r == k)
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{
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tr[site].sum[l&1][l&1] = data;
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return;
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}
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int m = (l+r)>>1;
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if(m >= k)
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Change(site<<1,l,m,k,data);
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else
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Change(site<<1|1,m+1,r,k,data);
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tr[site] = Joint(tr[site<<1],tr[site<<1|1]);
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}
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LinkTree MAX(int site,int l,int r,int ll,int rr)
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{
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int i,j;
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LinkTree tmp;
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if(l == ll && r == rr)
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{
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return tr[site];
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}
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int m = (l+r)>>1;
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if(m >= rr) return MAX(site<<1,l,m,ll,rr);
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else if(m < ll) return MAX(site<<1|1,m+1,r,ll,rr);
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else
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{
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return Joint(MAX(site<<1,l,m,ll,m),MAX(site<<1|1,m+1,r,m+1,rr));
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}
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}
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int main()
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{
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int i,j,t,x,b,a;
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LL mm;
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LinkTree tmp;
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scanf("%d",&t);
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while(t--)
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{
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scanf("%d %d",&n,&m);
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SetTree(1,1,n);
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while(m--)
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{
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scanf("%d %d %d",&x,&a,&b);
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if(x) Change(1,1,n,a,b);
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else
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{
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tmp = MAX(1,1,n,a,b);
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mm = -Max;
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for(i = 0; i < 2; ++i)
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{
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for(j = 0; j < 2; ++j)
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{
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mm = max(mm,tmp.sum[i][j]);
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}
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}
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printf("%lld\n",mm);
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}
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}
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}
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return 0;
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}
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