标签:== back lan getchar 就是 make include main ios
就是线性代数的初等行变化:
#include <bits/stdc++.h>
#define mp make_pair
#define pb push_back
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef unsigned long long ull;
const double pi = acos(-1.0);
const double eps = 1e-7;
const int inf = 0x3f3f3f3f;
inline ll read() {
ll f = 1, x = 0;
char c = getchar();
while(c < ‘0‘ || c > ‘9‘) {
if(c == ‘-‘) f = -1;
c = getchar();
}
while(c >= ‘0‘ && c <= ‘9‘) {
x = (x << 1) + (x << 3) + (c ^ 48);
c = getchar();
}
return f * x;
}
const int N = 110;
double maze[N][N], ans[N];
int n;
bool Gauss() {
for(int i = 1; i <= n; i++) {
int max_r = i;
for(int j = i + 1; j <= n; j++)
if(fabs(maze[max_r][i]) < fabs(maze[j][i]))
max_r = j;
if(fabs(maze[max_r][i]) < eps) return true;
if(max_r != i) swap(maze[i], maze[max_r]);
double temp = maze[i][i];
for(int j = i; j <= n + 1; j++)
maze[i][j] /= temp;
for(int j = i + 1; j <= n; j++) {
temp = maze[j][i];
for(int k = i; k <= n + 1; k++)
maze[j][k] -= temp * maze[i][k];
}
}
for(int i = n; i >= 1; i--) {
ans[i] = maze[i][n + 1];
// ans[(int)maze[i][0]] = maze[i][n + 1];
for(int j = 1; j < i; j++) {
double temp = maze[j][i];
maze[j][i] -= temp;
maze[j][n + 1] -= maze[i][n + 1] * temp;
}
}
return false;
}
int main () {
// freopen("in.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
// ios::sync_with_stdio(false), cin.tie(0), cout.tie(0);
n = read();
for(int i = 1; i <= n; i++) {
maze[i][0] = i;
for(int j = 1; j <= n + 1; j++)
maze[i][j] = read();
}
if(Gauss()) {
puts("No Solution");
return 0;
}
for(int i = 1; i <= n; i++)
printf("%.2f\n", ans[i]);
return 0;
}
标签:== back lan getchar 就是 make include main ios
原文地址:https://www.cnblogs.com/lifehappy/p/13192837.html