http://acm.nyist.edu.cn/JudgeOnline/problem.php?pid=571
整数划分是一个经典的问题。请写一个程序,完成以下要求。
5 2
7
2
3
3
3
#include <iostream>
#include <cstring>
using namespace std;
int dp[150][150];
int n, k;
int main(){
while(cin >> n >> k){
//将n划分成若干正整数之和的划分数
for(int i = 0; i <= n; i++){
for(int j = 0; j <= n; j++){
if(i < j){
dp[i][j] = dp[i][i];
continue;
}
if(i == 1 || i == 0 || j == 1)
dp[i][j] = 1;
else
dp[i][j] = dp[i - j][j] + dp[i][j - 1];
}
}
int f3 = dp[n][k];
cout << dp[n][n] << endl;
memset(dp, 0, sizeof(dp));
// 将n划分成k个正整数之和的划分数。
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){
if(i < j){
dp[i][j] = 0;
continue;
}
if(j == 1){
dp[i][j] = 1;
}
else
dp[i][j] = dp[i - 1][j - 1] + dp[i - j][j];
}
}
cout << dp[n][k] << endl;
memset(dp, 0, sizeof(dp));
//将n划分成最大数不超过k的划分数。与第一个相同:
cout << f3 << endl;
memset(dp, 0, sizeof(dp));
//将n划分成若干个 奇正整数之和的划分数。
int ou[150][150];
ou[0][0] = dp[0][0] = 1;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){ //i,j必须从1开始!!!
if(i < j){
dp[i][j] = 0;
continue;
}
ou[i][j] = dp[i - j][j];
dp[i][j] = dp[i - 1][j - 1] + ou[i - j][j];
}
}
int sum = 0;
for(int i = 1; i <= n; i++){
sum += dp[n][i];
}
cout << sum << endl;
memset(dp, 0, sizeof(dp));
//将n划分成若干不同整数之和的划分数。
for(int i = 0; i <= n; i++){
for(int j = 0; j <= n; j++){
if(i < j){
dp[i][j] = dp[i][i];
continue;
}
if(i == 1 && j >= 1)
dp[i][j] = 1;
else if(i == 0)
dp[i][j] = 1;
else
dp[i][j] = dp[i - j][j - 1] + dp[i][j - 1];
}
}
cout << dp[n][n] << endl;
}
return 0;
}
不能ac的递归代码:
#include <iostream>
#include <cstring>
using namespace std;
int dp[105][105];
int n, k;
//将n划分成若干正整数之和的划分数
int fun1(int i, int j){
if(i < 0 || j < 0)
return 0;
if(dp[i][j])
return dp[i][j];
if(i == 0 || i == 1 || j == 1)
return dp[i][j] = 1;
return dp[i][j] = fun1(i - j, j) + fun1(i, j - 1);
}
// 将n划分成k个正整数之和的划分数。
int fun2(int i, int j){
if(i < 0 || j < 0)
return 0;
if(i < j)
return dp[i][j] = 0;
if(dp[i][j])
return dp[i][j];
if(j == 1){ //注意与上面的区别
return dp[i][j] = 1;
}
return dp[i][j] = fun2(i - 1, j - 1) + fun2(i - j, j);
}
//将n划分成若干个 奇正整数之和的划分数。
int fun3(int i, int j){
// if(i < 0 || j < 0)
// return 0;
// if(dp[i][j])
// return dp[i][j];
// if(i & 1 && j == 1){
// return dp[i][j] = 1;
// }
// return dp[i][j] = fun3(i - 1, j - 1) + fun3(i - 2 * j, j - 1);
int ou[150][150];
ou[0][0] = dp[0][0] = 1;
for(int i = 1; i <= n; i++){
for(int j = 1; j <= n; j++){ //i,j必须从1开始!!!
if(i < j){
dp[i][j] = 0;
continue;
}
ou[i][j] = dp[i - j][j];
dp[i][j] = dp[i - 1][j - 1] + ou[i - j][j];
}
}
}
int fun4(int i, int j){
if(i < 0 || j < 0)
return 0;
if(dp[i][j])
return dp[i][j];
if(i < j)
return dp[i][j] = fun4(i, i);
if(i == 1 && j >= 1)
return dp[i][j] = 1;
if(i == 0)
return dp[i][j] = 1;
return dp[i][j] = fun4(i - j, j - 1) + fun4(i, j - 1);
}
int main(){
while(cin >> n >> k){
cout << fun1(n, n) << endl;
memset(dp, 0, sizeof(dp));
cout << fun2(n, k) << endl;
memset(dp, 0, sizeof(dp));
cout << fun1(n, k) << endl;
memset(dp, 0, sizeof(dp));
int sum = 0;
fun3(n,n);
for(int i = 1; i <= n; i++){
sum += dp[n][i];
}
cout << sum << endl;
memset(dp, 0, sizeof(dp));
cout << fun4(n, n) << endl;
}
return 0;
}
//https://blog.csdn.net/lin_disguiser/article/details/50574818
原文:https://www.cnblogs.com/zhumengdexiaobai/p/9206145.html