线段树题单练习题解

线段树题单练习题解

题单

1 hdu 1166

#include <bits/stdc++.h>
using namespace std;

const int N = 	5e4+5;

typedef long long ll;

int t, n, p, a, b;
char op[10];
ll val;

ll tree[N<<2];

void push_up(int rt){
    tree[rt] = tree[rt<<1] + tree[rt<<1|1];
}
void build(int rt, int l, int r){
    if(l==r){
        scanf("%lld", &tree[rt]);
    }else{
        int mid = (l+r)>>1;
        build(rt<<1, l, mid);
        build(rt<<1|1, mid+1, r);
        push_up(rt);
    }
}

void modify(int rt, int l, int r, int p, ll v){
    tree[rt] += v;
    if(l==r) return;
    int mid = (l+r)>>1;
    if(p <= mid) modify(rt<<1, l, mid, p, v);
    else modify(rt<<1|1, mid+1, r, p, v);
    push_up(rt);
}

ll query(int rt, int l, int r, int ql, int qr){
    if(ql <= l && qr >= r){
        return tree[rt];
    }else{
        ll ans = 0;
        int mid = (l+r)>>1;
        if(ql <= mid){
            ans += query(rt<<1, l, mid, ql, qr);
        }
        if(qr > mid){
            ans += query(rt<<1|1, mid+1, r, ql, qr);
        }
        return ans;
    }
}


int main(){
    scanf("%d", &t);
    for(int _ = 1; _ <= t; ++_){
        printf("Case %d:\n", _);
        scanf("%d", &n);
        build(1, 1, n);
        while (1) {
            getchar();
            scanf("%s", op);
            if(*op == 'Q'){
                scanf("%d%d", &a, &b);
                printf("%lld\n", query(1, 1, n, a, b));
            }else if(*op == 'A'){
                scanf("%d%lld", &p, &val);
                modify(1, 1, n, p, val);
            }else if(*op == 'S'){
                scanf("%d%lld", &p, &val);
                modify(1, 1, n, p, -val);
            }else{
                break;
            }
        }
    }
    
    return 0;
}

hdu 1754

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int N = 2e5+5;

int n, m, a, b, p;
ll v;
char op[10];
ll arr[N];
ll tree[N<<2];

inline ll Max(ll a, ll b){
    return a>b?a:b;
}

void build(int rt, int l, int r){
    if(l==r){
        scanf("%lld", &tree[rt]);
    }else{
        int mid = l+r>>1;
        build(rt<<1, l, mid);
        build(rt<<1|1, mid+1, r);
        tree[rt] = Max(tree[rt<<1], tree[rt<<1|1]);
    }
}

void modify(int rt, int l, int r, int p, ll v){
    tree[rt] = Max(tree[rt], v);
    if(l==r)return;
    int mid = l+r>>1;
    if(p <= mid) modify(rt<<1, l, mid, p, v);
    else modify(rt<<1|1, mid+1, r, p, v);
}

ll query(int rt, int l, int r, int ql, int qr){
    if(ql <= l && qr >= r) return tree[rt];
    else{
        ll ans = 0;
        int mid = l+r>>1;
        if(ql <= mid){
            ans = query(rt<<1, l, mid, ql, qr);
        }
        if(qr > mid){
            ans = Max(ans, query(rt<<1|1, mid+1, r, ql, qr));
        }
        return ans;
    } 
}


int main(){
    while(scanf("%d%d", &n, &m) != EOF){
        build(1, 1, n);
        while(m--){
            getchar();
            scanf("%s", op);
            if(*op == 'Q'){
                scanf("%d%d", &a, &b);
                printf("%lld\n", query(1, 1, n, a, b));
            }else{
                scanf("%d%lld", &p, &v);
                modify(1, 1, n, p, v);
            }
        }
    }

    return 0;
}