codeforces 272c

codeforces 272c

​​ Dima’s got a staircase that consists of n stairs. The first stair is at height a1, the second one is at a2, the last one is at an (1 ≤ a1 ≤ a2 ≤ … ≤ an).

Dima decided to play with the staircase, so he is throwing rectangular boxes at the staircase from above. The i-th box has width wi and height hi. Dima throws each box vertically down on the first wi stairs of the staircase, that is, the box covers stairs with numbers 1, 2, …, wi. Each thrown box flies vertically down until at least one of the two following events happen:

the bottom of the box touches the top of a stair; the bottom of the box touches the top of a box, thrown earlier. We only consider touching of the horizontal sides of stairs and boxes, at that touching with the corners isn’t taken into consideration. Specifically, that implies that a box with width wi cannot touch the stair number wi + 1.

You are given the description of the staircase and the sequence in which Dima threw the boxes at it. For each box, determine how high the bottom of the box after landing will be. Consider a box to fall after the previous one lands.

Input The first line contains integer n (1 ≤ n ≤ 105) — the number of stairs in the staircase. The second line contains a non-decreasing sequence, consisting of n integers, a1, a2, …, an (1 ≤ ai ≤ 109; ai ≤ ai + 1).

The next line contains integer m (1 ≤ m ≤ 105) — the number of boxes. Each of the following m lines contains a pair of integers wi, hi (1 ≤ wi ≤ n; 1 ≤ hi ≤ 109) — the size of the i-th thrown box.

The numbers in the lines are separated by spaces.

Output Print m integers — for each box the height, where the bottom of the box will be after landing. Print the answers for the boxes in the order, in which the boxes are given in the input.

Please, do not use the %lld specifier to read or write 64-bit integers in C++. It is preferred to use the cin, cout streams or the %I64d specifier.

Examples Input 5 1 2 3 6 6 4 1 1 3 1 1 1 4 3 Output 1 3 4 6 Input 3 1 2 3 2 1 1 3 1 Output 1 3 Input 1 1 5 1 2 1 10 1 10 1 10 1 10 Output 1 3 13 23 33 Note The first sample are shown on the picture.

由于每次我都是从第一个开始放 所以我只需要贪心的找一下我的头和尾哪个大一些然后那么我放的位置一定是那个大的地方

#include#include#define N 110000using namespace std;inline int read(){ int x=0;char ch=getchar(); while (ch<'0'||ch>'9') ch=getchar(); while (ch<='9'&&ch>='0'){x=x*10+ch-'0';ch=getchar();} return x;}int n,m;long long a[N];int main(){// freopen("cf.in","r",stdin); n=read(); for (int i=1;i<=n;++i) a[i]=read(); m=read(); for (int i=1;i<=m;++i){ int w=read(),h=read();long long ans=max(a[1],a[w]); printf("%I64d\n",ans);if (1==w) a[1]+=h;else a[1]=ans+h,a[w]=ans+h; } return 0;}

还可以用线段树维护下最大值

#include#include#define N 110000using namespace std;inline int read(){ int x=0;char ch=getchar(); while (ch<'0'||ch>'9') ch=getchar(); while (ch<='9'&&ch>='0'){x=x*10+ch-'0';ch=getchar();} return x;}struct node{ int l,r,left,right;long long max,lazy;}tree[N<<2];int num,n,a[N],root,m;inline void update(int x){ int l=tree[x].left,r=tree[x].right; tree[x].max=max(tree[l].max,tree[r].max);}void build(int &x,int l,int r){ x=++num;tree[x].l=l;tree[x].r=r; if (l==r){tree[x].max=a[l];return ;} int mid=l+r>>1; build(tree[x].left,l,mid);build(tree[x].right,mid+1,r); update(x);}inline void pushdown(int x){ if(!tree[x].lazy) return; int l=tree[x].left,r=tree[x].right; tree[r].lazy=tree[l].lazy=tree[x].lazy; tree[r].max=tree[l].max=tree[x].max;tree[x].lazy=0;}long long query(int x,int l,int r){ if (l<=tree[x].l&&r>=tree[x].r)return tree[x].max; int mid=tree[x].l+tree[x].r>>1;pushdown(x);long long tmp=0; if (l<=mid) tmp=max(tmp,query(tree[x].left,l,r)); if (r>mid) tmp=max(tmp,query(tree[x].right,l,r)); return tmp;}void change(int x,int l,int r,long long v){ if (l<=tree[x].l&&r>=tree[x].r) { tree[x].lazy=v,tree[x].max=v;return; } int mid=tree[x].l+tree[x].r>>1;pushdown(x); if (l<=mid) change(tree[x].left,l,r,v); if (r>mid) change(tree[x].right,l,r,v);update(x);}int main(){// freopen("cf.in","r",stdin); n=read(); for (int i=1;i<=n;++i) a[i]=read(); build(root,1,n);m=read(); for (int i=1;i<=m;++i){ int w=read(),h=read();long long ans=query(root,1,w); printf("%I64d\n",ans); change(root,1,w,ans+h); } return 0;}

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