update

src/8/16/trionic-array-ii.cpp

@@ -0,0 +1,53 @@
+#include <bits/stdc++.h>
+#include <iostream>
+#include <vector>
+using namespace std;
+
+class Solution {
+public:
+    long long maxSumTrionic(vector<int>& nums) {
+        vector<int> dp(nums.size());
+        cout<<dp[0]<<',';
+        int ans = INT_MIN;
+        for(int i=1;i<nums.size();i++){
+            if(nums[i]<=nums[i-1]){
+                dp[i]=dp[i-1];
+            }else{
+                dp[i]=i;
+            }
+            cout<<dp[i]<<',';
+        }
+        cout<<'\n';
+        for(int i=1;i<nums.size()-1;i++){
+            cout<<"i:"<<i<<'\n';
+            if(i+1<nums.size() && dp[i+1]==dp[i])continue;
+            if(dp[i]==i)continue;
+            if(dp[i]==0 || dp[i+1]==dp[i])continue;
+            int l = dp[i],r=i+1;
+            int lsum = nums[dp[i]-1],rsum=nums[i+1],rbegin=nums[i+1];
+            while(l-1>0 && (l==1||dp[l-1]!=dp[l-2]) && nums[l]>0){
+                l--;
+                lsum+=nums[l];
+                cout<<"l:"<<l<<'\n';
+            }
+            while(r<nums.size()-1 && (r==nums.size()-1||dp[r]!=dp[r+1])){
+                r++;
+                rsum+=nums[r];
+                cout<<"r:"<<r<<'\n';
+            }
+            int mid = 0;
+            for(int j=dp[i];j<=i;j++){
+                mid+=nums[j];
+            }
+            ans=max(ans,mid+lsum+max(rsum,rbegin));
+            cout<<mid+lsum+max(rsum,rbegin)<<'\n';
+        }
+        return ans;
+    }
+};
+
+int main(){
+    Solution s;
+    vector<int> v={1,4,2,7};
+    cout<<s.maxSumTrionic(v)<<'\n';
+}

src/8/18/segtree_add.cpp

@@ -0,0 +1,72 @@
+#include <algorithm>
+#include <cstdint>
+#include <iostream>
+#include <limits>
+#include <vector>
+
+using ll = int64_t;
+
+std::vector<ll> t;
+std::vector<ll> nums;
+
+ll create(ll l, ll r, ll idx) {
+    if (l == r) {
+        t[idx] = nums[l];
+        return t[idx];
+    }
+    ll mid = (l + r) / 2;
+    t[idx] = std::min(create(l, mid, 2 * idx + 1), create(mid + 1, r, 2 * idx + 2));
+    return t[idx];
+}
+
+void update(ll l, ll r, ll idx, ll pos, ll val) {
+    if (l == r) {
+        t[idx] = val;
+        return;
+    }
+    ll mid = (l + r) / 2;
+    if (pos <= mid) {
+        update(l, mid, 2 * idx + 1, pos, val); 
+    } else {
+        update(mid + 1, r, 2 * idx + 2, pos, val);
+    }
+    t[idx] = std::min(t[2 * idx + 1], t[2 * idx + 2]);
+}
+
+ll query(ll cur,ll ql,ll qr,ll l,ll r){
+    if(qr<l || r<ql)return std::numeric_limits<ll>::max();
+    if(ql<=l && r<=qr)return t[cur];
+    ll mid = (l+r)/2;
+    return std::min(
+        query(cur*2+1, ql, qr, l, mid),
+        query(cur*2+2, ql, qr, mid+1, r)
+    );
+}
+
+int main(){
+    // 区间min 单点修改
+    ll n;
+    std::cin>>n;
+    t.resize(4*n);
+    nums.resize(n);
+    for(ll i=0; i<n; i++){
+        std::cin>>nums[i];
+    }
+    create(0, n - 1, 0);
+    ll q;
+    std::cin>>q;
+    while(q--){
+        ll idx, val;
+        std::cin>>idx>>val;
+        idx--;
+        update(0, n - 1, 0, idx, val);
+        std::cout << t[0] << "\n";
+    }
+    std::cin>>q;
+    while(q--){
+        ll l,r;
+        std::cin>>l>>r;
+        l++,r++;
+        std::cout<<query(0, l, r, 0, n-1)<<'\n';
+    }
+}