Mathematical modelling How to cross the river with a boat carrying 3 people at a time, and 4 merchan

Are there any restrictions???

If not, just go over 3 people and 1 person come back.

I'll give you a mathematics program :

a = ,d = ,i = 1;

j = 1;

k = 1;

s[0] = s[1] = ;

print["This shore --- --- opposite the shore on the ship"];

do[do[s[i + 1] = s[i] +1)^i d[[j]];

t = 0;

do[if[s[i + 1] == a[[k]],t = 1],if[t == 0, continue]

z = mod[i + 1, 2];

u = 0;

if[i + 1 >= 3,do[if[s[i + 1] == s[m], u = 1; break]

if[u == 0, c[i + 1] = d[[j]];break]

if[t == 0, print[no result]; break]

b[i + 1] = -s[i + 1];

print[s[i], "---", c[i + 1], "---", b[i + 1]];

if[s[i + 1] == , break]

Go run it yourself, think about it, it's simple.

Summary. 1. Three followers go and one follower returns;

2. Two retinues go and one retinue returns;

3. Three merchants passed, one merchant and one retinue returned;

4. Two merchants passed, and one retinue returned;

5. Three retinues in the past.

Mathematical model 4 merchants, 4 retinues, a small boat can accommodate up to 3 people, how to arrange a ferry, what capacity of a small boat can safely cross the river.

1. Three retinues went by chance, and one retinue returned; 2, two followers of the stupid group went over, and one follower returned; 3. Three merchants passed, one merchant and an entourage with a gear change key came back; 4. Two merchants passed, and one retinue returned; 5. Three retinues in the past.

Hello, it can be like this.

Three people capacity.

I mean in the form of mathematical modeling.

And it is the capacity of the ship that is asked.

That's pretty much what it looks like.

Okay thank you.

Jiang Qiyuan's book "Mathematical Modeling" has a detailed explanation.

1. Two retinues go and one retinue returns.

2. Two more followers go and one follower returns.

3. Two merchants passed, an attendant and a merchant returned. (This step is the point) 4, two merchants go over, and one retinue returns.

5. Two retinues go and one retinue returns.

6. The last two retinues passed.

Businessman A, B, C, D

Retinue a, b, c, d

aa crosses the river, a returns.

ab Cross the river and come back.

ab crosses the river, b returns.

BC crosses the river, C returns.

cc crosses the river, c comes back to seep orange.

DC crosses the river, D comes back.

DD crosses the river and is empty.