POJ2763 Housewife Wind
树链剖分边更新,线段树单点更新,区间查询
1 #include <cstdio> 2 #include <cstring> 3 #include <algorithm> 4 #include <cstdlib> 5 using namespace std; 6 #define lson l,m,rt<<1 7 #define rson m+1,r,rt<<1|1 8 const int maxn = 100005; 9 int siz[maxn],son[maxn],fa[maxn],dep[maxn],top[maxn],tid[maxn],lable; 10 int head[maxn],cnt; 11 struct edge 12 { 13 int v,w,en,next; 14 }e[maxn*2]; 15 int n,m,s; 16 int sum[maxn<<2]; 17 void init() 18 { 19 memset(head,-1,sizeof(head)); 20 cnt = lable = 0; 21 } 22 void add(int u,int v,int w) 23 { 24 e[cnt].v = v; 25 e[cnt].w = w; 26 e[cnt].next = head[u]; 27 head[u] = cnt++; 28 } 29 void find_heavy(int rt,int father,int depth) 30 { 31 //printf("rt=%d fa=%d \n",rt,father); 32 fa[rt] = father; 33 son[rt] = 0; 34 dep[rt] = depth; 35 siz[rt] = 1; 36 int maxsize = 0; 37 for(int i = head[rt];i!=-1;i = e[i].next)if(e[i].v!=father) 38 { 39 e[i].en = e[i^1].en = e[i].v; 40 find_heavy(e[i].v,rt,depth+1); 41 siz[rt]+=siz[e[i].v]; 42 if(siz[e[i].v]>maxsize) 43 maxsize = siz[e[i].v],son[rt] = e[i].v; 44 } 45 } 46 void connect(int rt,int anc) 47 { 48 tid[rt] = ++lable; 49 top[rt] = anc; 50 if(son[rt])connect(son[rt],anc); 51 for(int i = head[rt];i!=-1;i = e[i].next) 52 if(e[i].v!=fa[rt]&&e[i].v!=son[rt]) 53 connect(e[i].v,e[i].v); 54 } 55 void pushup(int rt) 56 { 57 sum[rt] = sum[rt<<1]+sum[rt<<1|1]; 58 } 59 void update(int pos,int val,int l,int r,int rt) 60 { 61 if(l==r){ 62 sum[rt] = val; 63 return; 64 } 65 int m = (l+r)>>1; 66 if(pos<=m)update(pos,val,lson); 67 else update(pos,val,rson); 68 pushup(rt); 69 } 70 int query(int L,int R,int l,int r,int rt) 71 { 72 if(L<=l&&r<=R)return sum[rt]; 73 int m = (l+r)>>1,ret = 0; 74 if(L<=m)ret+=query(L,R,lson); 75 if(m<R)ret+=query(L,R,rson); 76 return ret; 77 } 78 int getsum(int x,int y) 79 { 80 int ans = 0; 81 while(top[x]!=top[y]) 82 { 83 if(dep[top[x]]<dep[top[y]])swap(x,y); 84 ans+=query(tid[top[x]],tid[x],1,n,1); 85 x = fa[top[x]]; 86 } 87 if(dep[x]>dep[y])swap(x,y); 88 if(x==y)return ans; 89 ans+=query(tid[son[x]],tid[y],1,n,1); 90 return ans; 91 } 92 int main() 93 { 94 while(~scanf("%d%d%d",&n,&m,&s)) 95 { 96 init(); 97 for(int i = 1;i<n;++i) 98 { 99 int u,v,w;scanf("%d%d%d",&u,&v,&w); 100 add(u,v,w); 101 add(v,u,w); 102 } 103 // for(int i = 1;i<=n;++i){ 104 // printf("i=%d:",i); 105 // for(int j = head[i];j!=-1;j = e[j].next) 106 // { 107 // printf("%d ",e[j].v); 108 // system("pause"); 109 // } 110 // puts(""); 111 // } 112 find_heavy(1,1,1);//puts("----------"); 113 connect(1,1); 114 115 for(int i = 0;i<cnt;i+=2)update(tid[e[i].en],e[i].w,1,n,1); 116 while(m--) 117 { 118 int a,b,c;scanf("%d",&a); 119 if(a){ 120 scanf("%d%d",&b,&c); 121 update(tid[e[2*b-1].en],c,1,n,1); 122 } 123 else { 124 scanf("%d",&b); 125 printf("%d\n",getsum(s,b)); 126 s = b; 127 } 128 } 129 } 130 return 0; 131 }
弱者究竟为何而战?!