【練習09】簡單動態規劃 1002 Max Sum

第一次提交的代碼使用了遞迴，而由於資料比較大遞迴的層數比較多，導致出現了“棧溢出”。

第一次提交代碼：

//模板開始#include <string>   #include <vector>   #include <algorithm>   #include <iostream>   #include <sstream>   #include <fstream>   #include <map>   #include <set>   #include <cstdio>   #include <cmath>   #include <cstdlib>   #include <ctime>#include<iomanip>#define SZ(x) (int(x.size()))using namespace std;int toInt(string s){istringstream sin(s); int t; sin>>t; return t;}template<class T> string toString(T x){ostringstream sout; sout<<x; return sout.str();}typedef long long int64;int64 toInt64(string s){istringstream sin(s); int64 t; sin>>t;return t;}template<class T> T gcd(T a, T b){ if(a<0) return gcd(-a, b);if(b<0) return gcd(a, -b);return (b == 0)? a : gcd(b, a % b);}//模板結束（通用部分）//【練習09】簡單動態規劃 1002 Max Sum int calculate_add_max(int* datas, int* add_max, int j, int n){if(j == n - 1){return datas[n - 1];}else{add_max[j + 1] = calculate_add_max(datas, add_max, j + 1, n);if(add_max[j + 1] > 0){return datas[j] + add_max[j + 1];}else{return datas[j];}}}int main(){ifstream ifs("shuju.txt", ios::in);int cases;int n;int datas[100005];int add_max[100005];//ifs>>cases;cin>>cases;for(int i = 0;  i < cases; i++){//ifs>>n;cin>>n;for(int j = 0; j < n; j++){//ifs>>datas[j];cin>>datas[j];}add_max[0] = calculate_add_max(datas, add_max, 0, n);int max = add_max[0];int max_index = 0;for(int j = 0; j < n; j++){if(add_max[j] > max){max = add_max[j];max_index = j;}}int j;for(j = max_index + 1; j < n; j++){if(add_max[j] <= 0){cout<<"Case "<<i + 1<<":"<<endl;cout<<add_max[max_index]<<" "<<max_index + 1<<" "<<j<<endl;if(i != cases - 1){cout<<endl;}break;}else{continue;}}if(j == n){cout<<"Case "<<i + 1<<":"<<endl;cout<<add_max[max_index]<<" "<<max_index + 1<<" "<<n<<endl;if(i != cases - 1){cout<<endl;}}}return 0;}

 

 放棄遞迴，改用“遞推”後成功AC。

第二次提交代碼：

//模板開始#include <string>   #include <vector>   #include <algorithm>   #include <iostream>   #include <sstream>   #include <fstream>   #include <map>   #include <set>   #include <cstdio>   #include <cmath>   #include <cstdlib>   #include <ctime>#include<iomanip>#define SZ(x) (int(x.size()))using namespace std;int toInt(string s){istringstream sin(s); int t; sin>>t; return t;}template<class T> string toString(T x){ostringstream sout; sout<<x; return sout.str();}typedef long long int64;int64 toInt64(string s){istringstream sin(s); int64 t; sin>>t;return t;}template<class T> T gcd(T a, T b){ if(a<0) return gcd(-a, b);if(b<0) return gcd(a, -b);return (b == 0)? a : gcd(b, a % b);}//模板結束（通用部分）//【練習09】簡單動態規劃 1002 Max Sum int calculate_add_max(int* datas, int* add_max, int j){return add_max[j + 1]>0?datas[j]+add_max[j + 1]:datas[j];}int main(){ifstream ifs("shuju.txt", ios::in);int cases;int n;int datas[100005];int add_max[100005];//ifs>>cases;cin>>cases;for(int i = 0;  i < cases; i++){//ifs>>n;cin>>n;for(int j = 0; j < n; j++){//ifs>>datas[j];cin>>datas[j];}add_max[n - 1] = datas[n - 1];for(int j = n - 2; j >= 0; j--){add_max[j] = calculate_add_max(datas, add_max, j);}int max = add_max[0];int max_index = 0;for(int j = 0; j < n; j++){if(add_max[j] > max){max = add_max[j];max_index = j;}}int j;for(j = max_index + 1; j < n; j++){if(add_max[j] <= 0){cout<<"Case "<<i + 1<<":"<<endl;cout<<add_max[max_index]<<" "<<max_index + 1<<" "<<j<<endl;if(i != cases - 1){cout<<endl;}break;}else{continue;}}if(j == n){cout<<"Case "<<i + 1<<":"<<endl;cout<<add_max[max_index]<<" "<<max_index + 1<<" "<<n<<endl;if(i != cases - 1){cout<<endl;}}}return 0;}