codeforces772C
给一段序列，给你去掉所有数字的顺序，输出每去掉一个数，当前联通的子序列的最大值。
倒着来，每次插入一个数，然后求联通的最大值，线段树每个节点标记一下，区间的左右是否插入了数字，还有如果有数字从左边/右边开始连续子序列的值，还有这个节点的区间是否连续。
1 #include <cstdio> 2 3 #include <algorithm> 4 5 using namespace std; 6 7 typedef long long LL; 8 9 const int maxn=100000; 10 11 int n; 12 13 int i; 14 15 int a[maxn+10]; 16 17 int b[maxn+10]; 18 19 LL res[maxn+10]; 20 21 struct node{ 22 int l,r; 23 LL sum; 24 int lflag,rflag; 25 LL lval,rval; 26 bool f; 27 }tree[maxn*4+10]; 28 29 void push_up(int id){ 30 int llf=tree[id<<1].lflag; 31 int lrf=tree[id<<1].rflag; 32 int rlf=tree[(id<<1)+1].lflag; 33 int rrf=tree[(id<<1)+1].rflag; 34 if(lrf&&rlf){ 35 tree[id].sum=max(max(tree[id<<1].rval+tree[(id<<1)+1].lval,tree[id<<1].sum),tree[(id<<1)+1].sum); 36 tree[id].lflag=llf; 37 tree[id].rflag=rrf; 38 if(llf){ 39 if(tree[id<<1].f) 40 tree[id].lval=tree[id<<1].lval+tree[(id<<1)+1].lval; 41 else tree[id].lval=tree[id<<1].lval; 42 } else { 43 tree[id].lval=0; 44 } 45 if(rrf){ 46 if(tree[(id<<1)+1].f){ 47 tree[id].rval=tree[(id<<1)].rval+tree[(id<<1)+1].rval; 48 } 49 else tree[id].rval=tree[(id<<1)+1].rval; 50 } else { 51 tree[id].rval=0; 52 } 53 tree[id].f=tree[(id<<1)].f&&tree[(id<<1)+1].f; 54 }else if(!lrf||!rlf){ 55 if(tree[id<<1].sum>tree[(id<<1)+1].sum){ 56 tree[id].sum=tree[id<<1].sum; 57 tree[id].lflag=llf; 58 tree[id].rflag=rrf; 59 if(!llf) 60 tree[id].lval=0; 61 else tree[id].lval=tree[id<<1].lval; 62 if(!rrf) 63 tree[id].rval=0; 64 else 65 tree[id].rval=tree[(id<<1)+1].rval; 66 tree[id].f=0; 67 } else if(tree[id<<1].sum<tree[(id<<1)+1].sum){ 68 tree[id].sum=tree[(id<<1)+1].sum; 69 tree[id].lflag=llf; 70 tree[id].rflag=rrf; 71 if(!llf) 72 tree[id].lval=0; 73 else tree[id].lval=tree[id<<1].lval; 74 if(!rrf) 75 tree[id].rval=0; 76 else 77 tree[id].rval=tree[(id<<1)+1].rval; 78 tree[id].f=0; 79 } else if(tree[id<<1].sum==tree[(id<<1)+1].sum){ 80 tree[id].sum=tree[id<<1].sum; 81 tree[id].lflag=llf; 82 tree[id].rflag=rrf; 83 if(!llf) 84 tree[id].lval=0; 85 else tree[id].lval=tree[id<<1].lval; 86 if(!rrf) 87 tree[id].rval=0; 88 else 89 tree[id].rval=tree[(id<<1)+1].rval; 90 tree[id].f=0; 91 } 92 93 } 94 } 95 96 void build(int id,int l,int r){ 97 if(l==r){ 98 tree[id].l=tree[id].r=l; 99 tree[id].sum=0; 100 tree[id].lflag=tree[id].rflag=0; 101 tree[id].lval=tree[id].rval=0; 102 tree[id].f=0; 103 return ; 104 } 105 int mid=(l+r)>>1; 106 build(id<<1,l,mid); 107 build((id<<1)+1,mid+1,r); 108 push_up(id); 109 } 110 111 void update(int id,int l,int r,int x,int val){ 112 if(l==r){ 113 tree[id].sum+=(LL)val; 114 tree[id].lflag=tree[id].rflag=1; 115 tree[id].lval=tree[id].rval=val; 116 tree[id].f=1; 117 return ; 118 } 119 int mid=(l+r)>>1; 120 if(x<=mid){ 121 update(id<<1,l,mid,x,val); 122 } else { 123 update((id<<1)+1,mid+1,r,x,val); 124 } 125 push_up(id); 126 } 127 128 int main() 129 { 130 scanf("%d",&n); 131 build(1,1,n); 132 for(i=1;i<=n;i++){ 133 scanf("%d",&a[i]); 134 } 135 for(i=1;i<=n;i++){ 136 scanf("%d",&b[i]); 137 } 138 for(i=n;i>=2;i--){ 139 update(1,1,n,b[i],a[b[i]]); 140 res[i]=tree[1].sum; 141 } 142 for(int i=2;i<=n+1;i++){ 143 printf("%I64d\n",res[i]); 144 } 145 return 0; 146 }
