Metal-Nonmetal Bond Candidate Matrix

Easy

A materials data platform stores a compact periodic-table snapshot and needs a simple matrix of all candidate ionic pairings. Table: Elements symbol: unique element code type: one of Metal, Nonmetal, Noble electrons: transfer metadata Noble has electrons = 0 Metal has electrons indicating electrons it can donate Nonmetal has electrons indicating electrons it can accept Pairing rule: A valid candidate pair is any combination of one Metal element and one Nonmetal element. No electron-equality condition is required. Noble elements never appear in the output. Task: Return all valid pairs in two columns: metal nonmetal Supported submission environments: SQL (SQLite 3.27.2) Pandas (Python)

Example 1

Input

Elements:
| symbol | type     | electrons |
|--------|----------|-----------|
| Ne     | Noble    | 0         |
| Na     | Metal    | 1         |
| Mg     | Metal    | 2         |
| Al     | Metal    | 3         |
| Cl     | Nonmetal | 1         |
| O      | Nonmetal | 2         |
| N      | Nonmetal | 3         |

Output

[
  {"metal":"Al","nonmetal":"Cl"},
  {"metal":"Al","nonmetal":"N"},
  {"metal":"Al","nonmetal":"O"},
  {"metal":"Mg","nonmetal":"Cl"},
  {"metal":"Mg","nonmetal":"N"},
  {"metal":"Mg","nonmetal":"O"},
  {"metal":"Na","nonmetal":"Cl"},
  {"metal":"Na","nonmetal":"N"},
  {"metal":"Na","nonmetal":"O"}
]

Explanation

There are 3 metals and 3 nonmetals, so the result contains 3 x 3 = 9 combinations. Noble element Ne is ignored.

Example 2

Input

Elements:
| symbol | type  | electrons |
|--------|-------|-----------|
| He     | Noble | 0         |
| Ar     | Noble | 0         |
| Li     | Metal | 1         |
| Be     | Metal | 2         |

Output

[]

Explanation

There are no Nonmetal rows, so no valid pair can be formed.

Example 3

Input

Elements:
| symbol | type     | electrons |
|--------|----------|-----------|
| K      | Metal    | 1         |
| Ca     | Metal    | 2         |
| F      | Nonmetal | 1         |
| S      | Nonmetal | 2         |
| Xe     | Noble    | 0         |

Output

[
  {"metal":"Ca","nonmetal":"F"},
  {"metal":"Ca","nonmetal":"S"},
  {"metal":"K","nonmetal":"F"},
  {"metal":"K","nonmetal":"S"}
]

Explanation

Each metal pairs with each nonmetal. The electrons column provides metadata but does not reduce pair count.

Constraints

0 <= number of rows in Elements <= 220
symbol values are unique
1 <= length(symbol) <= 12
type is one of: Metal, Nonmetal, Noble
0 <= electrons <= 8
If type = Noble, then electrons = 0
If type = Metal or Nonmetal, then electrons >= 1
Output must contain exactly two columns: metal and nonmetal
Return one row for each Metal x Nonmetal combination
For SQL submissions, use SQLite 3.27.2 semantics
For Pandas submissions, return a DataFrame with columns metal and nonmetal

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Metal-Nonmetal Bond Candidate Matrix

Easy

A materials data platform stores a compact periodic-table snapshot and needs a simple matrix of all candidate ionic pairings. Table: Elements symbol: unique element code type: one of Metal, Nonmetal, Noble electrons: transfer metadata Noble has electrons = 0 Metal has electrons indicating electrons it can donate Nonmetal has electrons indicating electrons it can accept Pairing rule: A valid candidate pair is any combination of one Metal element and one Nonmetal element. No electron-equality condition is required. Noble elements never appear in the output. Task: Return all valid pairs in two columns: metal nonmetal Supported submission environments: SQL (SQLite 3.27.2) Pandas (Python)

Example 1

Input

Elements:
| symbol | type     | electrons |
|--------|----------|-----------|
| Ne     | Noble    | 0         |
| Na     | Metal    | 1         |
| Mg     | Metal    | 2         |
| Al     | Metal    | 3         |
| Cl     | Nonmetal | 1         |
| O      | Nonmetal | 2         |
| N      | Nonmetal | 3         |

Output

[
  {"metal":"Al","nonmetal":"Cl"},
  {"metal":"Al","nonmetal":"N"},
  {"metal":"Al","nonmetal":"O"},
  {"metal":"Mg","nonmetal":"Cl"},
  {"metal":"Mg","nonmetal":"N"},
  {"metal":"Mg","nonmetal":"O"},
  {"metal":"Na","nonmetal":"Cl"},
  {"metal":"Na","nonmetal":"N"},
  {"metal":"Na","nonmetal":"O"}
]

Explanation

There are 3 metals and 3 nonmetals, so the result contains 3 x 3 = 9 combinations. Noble element Ne is ignored.

Example 2

Input

Elements:
| symbol | type  | electrons |
|--------|-------|-----------|
| He     | Noble | 0         |
| Ar     | Noble | 0         |
| Li     | Metal | 1         |
| Be     | Metal | 2         |

Output

[]

Explanation

There are no Nonmetal rows, so no valid pair can be formed.

Example 3

Input

Elements:
| symbol | type     | electrons |
|--------|----------|-----------|
| K      | Metal    | 1         |
| Ca     | Metal    | 2         |
| F      | Nonmetal | 1         |
| S      | Nonmetal | 2         |
| Xe     | Noble    | 0         |

Output

[
  {"metal":"Ca","nonmetal":"F"},
  {"metal":"Ca","nonmetal":"S"},
  {"metal":"K","nonmetal":"F"},
  {"metal":"K","nonmetal":"S"}
]

Explanation

Each metal pairs with each nonmetal. The electrons column provides metadata but does not reduce pair count.

Constraints

0 <= number of rows in Elements <= 220
symbol values are unique
1 <= length(symbol) <= 12
type is one of: Metal, Nonmetal, Noble
0 <= electrons <= 8
If type = Noble, then electrons = 0
If type = Metal or Nonmetal, then electrons >= 1
Output must contain exactly two columns: metal and nonmetal
Return one row for each Metal x Nonmetal combination
For SQL submissions, use SQLite 3.27.2 semantics
For Pandas submissions, return a DataFrame with columns metal and nonmetal